that they continue to grow long after education commences, and that if the intellectual faculties and moral sentiments be more educated by exercise than what they call the animal propensities, the fore and upper part of the head gives more and becomes larger in proportion than the hind part of the head. They farther allege that the shape of the head may alter very considerably, though more slowly in adults, and does alter if some organs of the mind, as they call certain portions of the brain, be more exercised than others. I do not consider what is called phrenology either precise enough or proved enough to rank with established science, but it is far more like a science than its opponents would represent it, and a great deal of useful knowledge is taught by phrenologists, along with not a little that has but little foundation in true observation. -PHILO. [12304.]-Phrenology." Saul Rymea" asks at what period of life the organs are developed. As our motto is Res non verba quaeso, I will answer him as briefly as possible. There is no period of life at which the organs will not grow if vigorously exercised. In childhood the propensities preponderate. Then the intellect becomes developed, and next the moral faculties. There is no definite time for the development of organisation after birth; circumstances tend greatly towards developing particular organs. If "Saul Rymen" is at all conversant with anatomy he must know that the brain is first formed before the boney particles are laid down, consequently the bones of the skull adapt themselves to the brain, and are not completely ossified for several years after birth. Now for the dilemma into which he presumes phrenology to be placed-viz., that the organs cannot grow after the skull becomes Ossified. Two processes are continually at work in the human frame-viz., absorption and deposition. Presuming an organ to be actively exercised, there is a considerable friction between the convolutions in action and the corresponding interior part of the cranium, and as a matter of course the waste matter is carried off by the absorbents. So active is this that in many cases of madness the skull becomes quite Bore and painful to the touch; in some cases quite worn through. I possess the skull of a drunkard worn in this manner in the region of the temples. Let "Saul" take a skull of any person (if known all the better), and place a light within it, and he will see the active organs where the light shines through. As to his belief or non-belief it matters little, the facts are the same, and we can say with Gall, This is truth, although at variance with the philosophy of ages.-W. CRISP. [12304.]-Phrenology.-"Saul Rymea" appears to think that the organs of the brain, according to phrenology, are indicated by "bumps" on the skull, whereas, in general, the surface of the skull is perfectly smooth, and it is only when an organ is developed in excess of the neighbouring organs that an elevation or protuberance is presented. The brain of a child at birth weighs about 10oz., and that of an adult from 24lb. to 31b. (Cavier's weighed 4lb. 10oz.); and as the brain of a child completely fills the skull, the latter must, of consequence, be considerably expanded and enlarged to contain the additional volume of brain when it reaches maturity. Any anatomist, without appealing to phrenology, will satisfy "Saul Rymea" on this point. Cavier states that the brain moulds itself in the cavity of the skull, which it fills exactly in such manner that knowledge of the bony part gives us information at least of the form of the exterior of the brain. It is patent to every one that the brain and skull of a child are considerably smaller than that of an adult, and hence both of them must be enlarged to a considerable extent before they arrive at maturity. How could this occur if the bones of the head are not "distorted by the soft mass of the brain"? The skull is not an adamantine barrier confining the brain within specific boundaries. Although a strong, it is a changeable covering, and will always accommodate itself to the development of the brain during its growth. There are many instances on record where in certain diseases of the brain the bead has been enlarged to twice its normal dimensions. How could this happen if the skull did not expand to meet the requirements of the enlarged brain? I hardly know what "Saul Rymea means when he states that "either the brain must have received its peculiar development before education steps in," &c. Surely, he does not suppose that education either creates or develops organs. It only intensifies their action or gives them more vigour, but Nature herself gives the tools, and education only applies them to their legitimate use.-NORTHUMBRIA. of my books. It may be Ononis campestris, a plant with pea-like, rose-coloured flowers, and leaves accom. panied by spines and prickles.-CORNUBIA. [12811.]—Hydraulic.-The well being 25ft. in depth, containing 10ft. of brackish water, there are 15ft. of rain water added to it, which, being intimately mixed, renders it tolerably palatable, and as long as the water is above the spring level, of course, no more brackish water will flow in. "Glaston's" error appears to be that he imagines that the two kinds of water ought to keep separate. Now, beer and water, differing considerably in specific gravity, can only be filled into a tumbler and caused to keep separate by interposing a silk handkerchief, and the slightest disturbance, such mingling. I very much doubt the possibility of any as pumping, would inevitably cause instant comtwo sorts of water being introduced into one receptacle without instantly intermixing. Also, it must be taken into account that when the natural spring level is added to, that it will flow back out of the well until the one balances the other.-A., Liverpool. [12811.]-Hydraulic.-The light water is on the top not only in the well but also in the tube, and therefore the light water comes out of the tube and the top of the tube is immediately again filled up with light water. The water moves round as the dotted lines show. The water moves like the air in this respect. If you open a barrel of beer, wine, &c., in the lower part you will get the fluid from the top.-H. MEYER. [12817.)-Red Prussiate of Potash may be prepared by acting on a solution of yellow prussiate with chlorine till it no longer gives a blue precipitate with iron persalts, evaporating and crystallising. -S. BOTTONE. [12318.]-Artificial Oils.-The oils mentioned are isomers, but have not as yet been converted into Oil of cinnamon and oil of winter green can be prepared artifically. See Roscoe's "Chemistry," 1871 edition.-S. BOTTONE. one another. [12819.]-Dyeing Pulp for Sugar Paper.-Add a small quantity of green copperas. You can get it as dark as you like by increasing the dose.-S. BOTTONE. [12321.]-Chess Player.-I have stated in my chess columns in the Gentleman's Journal, and also in the Echo Americano, that the automaton chess player at the Crystal Palace is moved and worked by a man who is concealed in the figure. I wrote a longer article on it about three or four years ago, which appeared in two or more German papers and was afterwards translated for the Dutch paper Sissa.H. MEYER. [12323.]-Scarecrows.-Try a set of model windmills, carrying pieces of looking-glass on the arms. Proved.-S. BOTTONE. [12381.]-Geometrical.-Let the given points be called A and B; join them. If the line A B be at right angles to the given line it is impossible to solve the problem, unless the points A and B be equidistant from the given line. If A B be not at right angles, bisect it, and through the point of bisection draw a straight line at right angles to A B. Produce it, and it will cut the given line in the required point. Prove by Euclid's "Elements," Book I., Prop. 4.-CERVUS. [12331.]-Geometrical.—With any radius exceeding half the distance between the points (their full distance is a good radius to take) strike arcs from each of them intersecting; and a straight line through their two intersections has any point in it equidistant from the two centres; consequently will cross your given line at the point required.-E. L. G. [12331.]-Geometrical.-L L1 = the given straight line. P and Q are the two given points. BP =B Q.-H. MEYER. [12886.]-Vine Root. -Cuttings from the vine may be struck in LQCA LPCL the early spring months, under glass.-S. BOT. B AB QA AP=AQ PAB=909 TONE. [12388.]-Hyacinth Bulbs are dried and stored in paper bags hung up. Plant out in October or November. -S. BOTTONE. [12305.]-Locomotives.-The principal advantage is that the heat is more fully utilised in a long-barrelled locomotive than in a short one, and, as a consequence more steam generated by the greater area of heating surface. There are also many disadvantages; a greater waste of boiler tubes by the blast cinders, and cost of repairs: but some engineers think that the Paste.-A few drops of carbolic acid, or a few grains one or two advantages of long-barrelled locomotives of corrosive sublimate, added to each pound of paste more than counterbalance their numerous defects.- made, will prevent mouldiness. Essential oil of cloves is also recommended.-S. BOTTONE. RAT-TAT. [12840.] - Flour [12306.] Botanical Names. The botanical [12848.]-Spanish Pronunciation.-The "th" name of the Persian or French willow is Epilobium sound is the only correct pronunciation; the "ss" is angustifolium, the flowers, which are purple, grow on a slovenly.-S. BOTTONE. long spike; the plant is a native of Britain-it will grow almost everywhere, even in the confined air of London. Its congener, Epilobium hirsutum, is a fine, showy plant, with large rose-coloured flowers. It thrives well in damp situations.-W. R. BIRT. [12348.)-Spanish Pronunciation. I wish some competent traveller would answer one part of this query—namely, whether what the grammars say of every %, or every theta (as Spaniards call it) really applies to that letter when final, as in the words vez, paz, cruz? I have heard natives of Spanish America. except when decidedly vulgar, so constantly give the th sound (sharp as in think) to both ce, ci, and the initial and medial z, as to leave no doubt of its correctness; and also give the final d, as of Verdad, Madrid, very near our flat th, as in the; but a final z I have only know whether this is an Americanism ?-E. L. G. heard sounded like English 2, and 1 should like to [12348.)-Spanish Pronunciation.-I beg to assure "Cast Steel" that the Castilians and inhabitants generally of the Northern provinces of Spain do most certainly pronounce the c before e or i, and the ≈ before any vowel, as th (hard), and not as s. They talk of Zaragoza, which they pronounce as if written Ciencia (pronounced Tharagotha, and they say Theénthia), meaning science. These peculiarities I my. self have heard in North Spain, especially in Old Castile, in Andalusia, the sounds given above are changed to that but I was told that in the southern provinces, especially of s sharp, and such words would be pronounced Saragosa, and seénsia. Though the Castilian is the purest form of pronunciation, I am inclined to think that the Andalusian form is of wider use, and it is the one which is almost invariably used in South America and the Spanish settlements.-WM. WRAY. storms.-A gentleman asked me the other day it [12359.]-Sulphurous Smell after ThunderI knew what was the cause of the sulphurous smell which succeeds a thunderstorm. I replied that it was generally attributed to the formation of ozone. But he said that it is a well known fact that there is no ozone in China (according to the usual tests), and yet the same peculiar smell is noticed. If any of your correspondents can verify or explain the circumstance, I shall be greatly obliged.-B. U. [12360.]-Pivots.-Will any brother inform me the best way to harden small drills for putting pivots into staffs, &c. ?-No SOFT SOlder. [12361.]-Carbon or Charcoal Pipes.-I wish to any reader describe the process ?-W. ALLAN. make some tobacco pipes of the above material. Will the content of the middle fustrum of a circular spindle? [12362.]-Formula.-What is the formula for finding W. ALLAN. [12363.] Recovering Indigo. I should feel obliged if any of "our" chemical correspondents would inform me how to recover indigo from other blues, I have a great quantity, and it grease, and dirt. should contain about 25 per cent. of indigo.-J. B. [12864]-Hoist.-I have made a hoist from a sketch by H. R. Gwastad, given in your very valuable journal, Feb. 9, 1872, reply 10561. Everything is fitted up in the best possible manner, friction pulleys are 4in. wide, and turned driving pulley on A shaft is 12in. diameter, strap 2in. wide. It will lift 601b. well, but I want to lift 14016. This it will not do. Will H. R. Gwastad or some other obliging correspondent tell me through your journal where I am at fault, as I have been at a considerable expense in fitting it up?-BOLTON TROTTER. [12365.]-Elder Flower Wine.-To each gallon of water put 4lb. of fine brown sugar, one lemon, and 1lb. of raisins. The raisins are to be picked. chopped, and put into the cask; boil the sugar and water, and pour it over the elder flowers, and when new milk warm, put a little yeast, and for each gallon of liquor put half a pint of elder flowers, which must be picked off when just ready to fall off the trees; pick them clear from stalks, then let all work in the tub a day or two, then turn into the cask on the raisins, and when done working bung up and keep for two months. The above is an excellent recipe, with this exception, the wine is never brisk and sparkling as it ought to be. Can any of your readers inform me wherein I fail to make it so ?— WAYNFLETE. [12366.]-Pianoforte without Strings.-I am much obliged to "The Harmonious Blacksmith" for his kind attention to my query respecting soundboards (12175). In his reply (p. 357) he alludes to a piano without strings, the patent of Mr. Goldsworthy, and also to one which he possesses, formed with vibrating spring bars, of which, probably, the sounding wire of an American clock is a rude yet apt illustration. Doubtless, as "The Harmonious Blacksmith" is a most ingenious and scientific mechanic, this piano of his is not only curious but harmonious-even an improvement on Mr. Goldsworthy's instrument, and, therefore, a description of it could not fail to be highly interesting to the readers of the ENGLISH MECHANIC. I trust he may regard it in this light, and be induced to give his fellow mechanics such a practical account of it as will set them all either constructing or thinking. A piano of this class has the pleasing peculiarity of remaining continually in tune, never requiring but the first tuning, a quality eminently desirable on shipboard. I think, too, it could be constructed more cheaply than the ordinary instrument.-E. B. FENNESSY. like to know whether "A., Liverpool" intends the piece Y SHIP. subscribers I have boys to educate, and as I am not tied [12353]-To Steady a Sketching Board.-May I trouble a correspondent to advise me about steadying a drawing-board, to which is attached an optical instrument, such as a camera lucida, in any place? I suppose a tripod stand is the most likely thing, but even that puzzles me in endeavouring to steady it, on stone pavement, for instance, and how about the wind?-POLOSEL [12394] Fret Saw.-I have a fret saw, which makes a rare clatter. What is the best arrangement for making the least noise ?-CHIP. [12395.]-Extracting Wax from Old Comb.How can I extract the wax from some old comb? I have tried boiling and straining it, but can get no war. I have been turning out some old hives, and want to do something with the comb, which is mostly black with age.-W. HAWKINS. [12367.] - Oval Turning.-I require to turn a number of pieces of hard wood of an oval form about fin. in thickness, and 84in. length of oval-having only a simple lathe I am confined to circles. Can any of "our" correspondents kindly inform me if any special form of lathe is required for ovals, or can it be managed by a chuck? If so, where are such chucks to be procured. where the relations of medical men enjoy certain ad- practical method of preparing rouge or plate powder as and the probable cost? Any information on the subject of oval turning will be acceptable.-PHOTO. BRIS TOLIENSIS. [12368]-Imitation Bronze.-I am exceedingly obliged to M. W. Bolton for the imitation bronze recipe, the effect of which is excellent. I, however, find a great difficulty in dissolving the corrosive sublimate. Ought it to be boiled in the vinegar, or would it be better to dissolve it in some kind of acid ?-J. W. C. [12389.]-Water Powder.-I want to get an instrument to make water powder (French poudre d'eau). On the continent I have met with a small apparatus is indiarubber of English make and patent, much cheaper and working nearly as well. Can any subscriber give me some information, as the makers I have asked about [12370.]-Liquid Rosin.-Will "Fiddler "allow me to ask him if he has tried the colophonium or liquid rosin lately advertised, and with what result?-L. J. V. G. [12371.)-Truss.-I shall be much obliged to any of your readers who can inform me where I can get a truss for rupture, that can be worn when bathing; or whether there is anything of the sort made specially for the purpose. The suffering is so intense when swimming that I am afraid I shall soon have to forego that pleasure it do not know such instrument?-L. J. V. G. unless I can get relief.-NOSBOR. [12372]-German Concertina.-I have been repairing a German concertina of my own at home, and I should like to know if any of "our" readers can tell me how to get out of my trouble, for I have made a set of four plates of tongues in steel instead of metal, but I cannot make them speak. I have tried every way, but I have failed.-AMATEUR. [12378.)-Softening Spring Water:-I have a deep well of excellent spring water, but unfortunately to hard for general domestic use. The interior circle of well is 3ft. 6in. diameter, with an average depth of 2ft. in water, which does not flow over at any time, nor fail in supply even in extreme dry seasons. I wish to know if some chemical production cannot be periodically put into the well, in proportion to the daily consumption of water, and thereby render the same more soft and effectual for its many services. As each bucket of water dipped from the well would probably weaken the action of any chemical influence through the continued supply from the spring, would it be more effectual if contained in a tank for daily use? Perhaps your talented and instructive correspondent, Mr. Bottone, will favour me with his suggestions for relief in this difficulty.-GILLEM, Ontario. [12374.1-Ancient Wrought Iron.-We are told by Mr. Forbes, F.R.S., in his report on the progress of the iron and steel industries (Feb., 1872), as a proof of the antiquity of iron smelting in India, and also of the large forgings in wrought iron which could be executed by a people who now appear to have entirely lost the art, the fact that Mr. Mallet has directed attention to a wrought-iron pillar situated at the mosque of the Kutub, near Delhi, which must be more than 1000, and may be as old as 1500, years; yet is as large as the screw-shaft of some of our largest steamships; that part of the column above the level of the soil being 48ft. high, with a diameter of 14ft. 4in. at the base, and 12in. at the top immediately below the elaborately chiselled capital. Are there any among your obliging correspondents who can throw more light upon this eventful period of early handicraft v. the present age of machinery ?-GILLEM, Ontario. [12375.]-Metallic Stain for Wood.-I have heard of such giving a very dark-almost black appearance to deal; afterwards to be varnished. Will one of "our" correspondents oblige me with name and mode of preparation?-GILLEM, Ontario. [12376.]-To "The Harmonious Blacksmith." -It would give me great pleasure to comply with the request contained in the postscript to letter 2416; but I scarcely know what it is on which my opinion is desired. If our friend will kindly lighten my darkness on this subject, he will oblige-BEACON LOUGH. [12377.]-Fall of a Bullet.-I was about sending a question on the following subject, when I happened to see Mr. Proctor's letter on "Spinning Tops and Gyroscopes" in your last issue. In this letter he says:-"It is, of course, perfectly true that gravity draws down the most swiftly travelling bullet-fired horizontally-so vantages as to fees, &c. I should prefer & seaport town or the neighbourhood of London, but this is not essential. Any particulars will be very acceptable to-PATER FAMILIAS. [12896.)-Rouge.-Will any kind friend tell me the made in factories (rouge and putty powder works) from sulphate of iron ?-L. T. W. [12397.]-Boatbuilding.-Will some reader kindly inform me what sort of wood the ribs and planking of Tonkes or any other electrician, if he would inform me [12382.]-Electrical.-I should feel grateful to Mr. boats are made of, whether the ribs are bent or cut to the required shape? Also, what shape the planks are in what book the particular subject of determining in-cut so as to get a straight gunwale; are they cut taperternal resistance of a battery by means of a tangent ing on both sides or only one?-W. S. galvanometer, the power of the two cells, amount of external resistance brought in by the introduction of coils. Although this is an old subject, yet in the books on the subject which I have studied, I have found it either entirely omitted or else skimmed over. Accordingly, if Mr. Tonkes would explain it fully or else name some book in which it is so done, I should be most deeply obliged, showing how the sine galvanometer differs from the tangent in construction. In reading a work on electricity, I saw it mentioned that a machine entirely made of guttapercha with rubbers of hareskin was both less expensive and also more powerful than a plate glass machine of the same size. I should be obliged if any of your contributors that have tried it would state their experience, and also the cost as compared to an average plate machine.-E. N. D. [12383.]-Working Perfect Plane Surfaces.-Will any reader kindly describe a good method of grinding perfect plane surfaces, and polishing the same?-R. ROBERTS. [12384.]-Coppering Carbon.-Will some reader of the MECHANIC please have the kindness to tell the easiest way of preparing carbon, so that copper plate may be soldered to it ?-F. J. WALL. [12385.]-Sulphur in Wall Papers.-I have recently had an air-tight glass case papered with an ultramarine paper, and find silver goods put in it discolour very rapidly, and as this stultifies the object of a glass case, I should be obliged if any "mechanic" would suggest & remedy to me. My idea is that there is sulphur in the colour, from the character of the tarnish. If so, I suppose there is no remedy but tearing off the paper and putting a new one.-GGUR. [12386.]-The Prevention of Incrustation in Steam Boilers.-Having proved that the use of a few pieces of oak (the greener the better) in a steam boiler prevents incrustation, I should like to inquire the why and wherefore of this. A dark powder results from the use of the oak, which half an hour's work will remove from the boiler, whereas formerly it occupied two of my workmen for two days, at intervals of a month, to chip off the incrustation with hammers, this being, besides, a hot, arduous, and irksome task.-J. D. K. [12887.)-Amateur Organ Building.-Thanks to "J. D." for kind attention to query 11887. I am sorry I did not mention at the time that the only room I have available is 13ft. long by 3ft. 6in. wide, so that I shall, under these circumstances, have to elongate the dimensions given, making the same area-viz., 7ft. by 2ft., allowing for Bourdon, which will have to be pat at the back. Will bellows of these dimensions be more difficult to make, and will double feeders be advisable to make it do its work well? Would it be better to make the Bourdon on a larger scale than 6in. by 54in. CCC, for the organ in the above mentioned query, or will it be powerful enough on a 2in. wind? Which is best, a Bourdon of small scale, well blown up, or one on a large scale, moderately winded? Of course, where room is the greatest consideration, the former is best, but which is really most efficient? I am glad to see that "J. D." is better, and hope to see soon a continuation of his interesting papers, as no doubt a great many besides myself are at a standstill for further instructions.-Y. Z. [12888.]-Onions.-Will any reader tell me which is the best kind of onion seed to sow at the end of July, in order to have very large onions for exhibition next summer, and yet have the property of keeping well. I have tried the Tripolian onion, but it does not keep very well after it is taken up.-A COAL MINER. 12389.]-Dirty Mercury.-I have a lot of mercury which seems to be adulterated with lead, tin, or some other combustible. Will any kind reader of the ENGLISH MECHANIC please to give some information as to the best way of cleaning ont the adulteration? Also, how is a barometer tube cleaned after being filled with the above ?—C., Glasgow. [12390.]-Chemical.-The writer would be obliged [12398.]-Silver and Gilt Articles.-Can some of the numerous readers of this journal give me a few hints on the best means of cleaning and restoring to its original colour old gilt, parcel gilt, and silver articles, without injuring the articles? Also, tell me how frosted silver can be cleaned and whitened? Is there any work on this subject from which I could get any information? Is frosting, burnishing, oxydising, &c., beyond the skill of an amateur ?-SPERO. [12399.]-Organ Building.-Will any of "our" readers interested in organ construction kindly give a description of the viol d'amour stop? Also say if there is any difference between the Wald and Claribel Autes, and which is the best way to arrange the pedal Bourdon when the room is only 8ft. high: to lay the pipes down and have vertical windchest, or to elbow them as reeds are sometimes done ?—Y. Z. [12400.]-Parrots.-Can any reader tell me the name of a pair of parrots that I have? Breasts and tops of heads bright scarlet, throats blue, backs red and black, lower parts of wings green and blue, tails light blue feet, horn coloured bills. They are about 12in. or 13. underneath and very dark blue on top, slate coloured in length, half of which is tail. I also want to know if they are likely to breed, for they feed each other like pigeons.-F. S. M. W. [12401.]-House Painting.-I am about to do some painting. Will any of "our" readers inform me what proportions of white lead, turps, boiled oil, and driers to use?-J. W. C. [12402.)-Grease on Leather Bands.-Can any fellow subscriber inform me if it is possible to take out grease from leather bands, so as to look new again?WHOLESALE. [12403.]-Brass Moulding.-Can any reader in form me what process lead has to undergo before it will mix with copper and zine? I have been told that it can be killed by some chemical-NOTTINGHAM. [12404.] Trigonometrical Theorems. -Tha following theorems can be deduced from Legendre, Lv. III, pr. 18, or from Euclid VI., 8. Will some mathematician furnish the deductions, either from Euclid or Legendre, and prove the same by trigenometry?-THETAMU (Horsham). [12405.]-Boiler for Model Steamboat.-Can any subscriber tell me what should be the shape and size of a boiler I should want for a model paddle steamboat 3in. depth of hold, 44in. beam, and 2ft. 8in. long? the size of my cylinders are four-fifths of an inch diameter, and 14in. deep. What material would be best 7-A. W. D. [12406.]-Worm-Eaten Violin.-I have an old violin, rather badly worm eaten, can any one tell me how to prevent further decay?-F. S. [12407.)-Checkering Tool-Can any correspondent inform me how to make a checkering tool for checkering hard wood or ivory: also how to make steel rings, 2in. long, lin. diameter, fin. thick, which ma sound?-A TRIMMER. [12408]-Quill Pens.-How are quills prepared to them for making pens.-SPERO. same.-E. B. that it reaches the ground as quickly as a ball dropped to any of your readers who can inform him of one of kindly inform me of one, or some of the simplest and from rest from the same height." In a book on practical mechanics a similar sentence to this is modified by the words "from the top of a high tower," being added to the phrase "fired horizontally." I can conceive of a bullet fired, and a ball or bullet simultaneously dropped, from the top of a tower 200ft. high reaching the ground simultaneously; but it seems to me impossible that a ball dropped from the height of 4ft. from the ground should take as long in falling as a bullet fired horizon. tally from the same height. I should be much obliged if Mr. Proctor would make this matter a little more clear-by diagrams if necessary-now that he has per formed a similar operation for the upward deflection of bullets.-PUZZLED. [12378.]-Bat Making.—What tool does a bat maker use in smoothing; and how do they make them hard so that they will not dent with the ball? Which is the best glue for glning in handles? Where can I get cane for handles ?-TIM. [12579)-Packing Piston Rings.-Referring to query 12158, concerning packing rings of piston, I would the best works on elementary chemistry suitable for a -HOME STUDENT. economists formed [12391.]-National Losses. Have any political under all heads which we, as a nation, are called on to any estimate of the absolute loss make good annually?-EXCELSIOR. [12832]-Bee Management.-In November last I became the possessor of three stocks of bees in straw hives. I know nothing of bee management, and the result was that two out of the three stocks died in May; the remaining stock is very light. In taking up the hives I found on the floor beard a number of maggots in. long, and protected with something like wool. In taking out the comb I found that the maggots had made maggots on the floor-board of my remaining hive. roads through it in all directions. I also found six I have made a wooden hive 1lin. square. My wish is to transfer the bees from straw hive to the wooden hive, how to do so I know not, as the straw and wooden hive are not the same size and shape. I wish to know how to transfer them, and when.-W. T. L. [12409.]-Transferring Pencil Drawings on Paper to Boxwood for Engraving.-Can any of me how to transfer your numerous readers inform Pencil drawings on paper to boxwood for engraving [12410.]-Chemical.-Will any of your subscribers which would have the power of preventing marine. most effectual ingredients, or basis of ingrediea animal, and vegetable matter from adhering to iron, b at the same time free from any damaging or corrosive not possess adhesive qualities. I want to apply i effects on iron? The substance I inquire about new conjunction with a composition which has the la named quality.-W. J. [12411.]-Expansion Joints.-Will any subscriber give description of one or two of the best expans) = joints for a long cast-iron gutter? State how far apar it is advisable to place them.-EXCELSIOR. counterforts be placed at right angles to abutments, t [12412]-Skew Bridge-In a skew bridge shon", parallel to face of arch ?-EXCELSIOR. [12413]-Harmonium-Will "Pneumatic Low-" oblige me with a design for a 44 row harmonium wij dimensions?-P. M. me know how to clean white feathers on the skim fr [12414]-Cleaning Feathers.-Will any one grease and blood stain.-3. S. What is the [12415.] Provision for Child. present value for five shillings per week to be paid with a child twelve months old until thirteen years old? How can I calculate this, or what must I allow for the child's risk of dying?-J. R. [12416)-Spinning.- How many revolutions per minute does the spindle make in spinning? How many twists are there per inch in twist, and also how many weft? I desire that the answer be particularly for cotton, but answers for other materials will be gratefully accepted.-J. R [12417.]-Hardening Spiral Springs.-If some brother reader would kindly inform me I should feel obliged. I have been hardening them in water and letting them blaze off with tallow, but I find them sometimes too hard, and more often too soft; they are 1/16in., fin., and fin. steel wire. I have tried putting them in oil without letting down, but they are too soft. The springs you buy are hardened very well, but you cannot always get them to suit you.-SPRINGS. [12418]-Resistance of Steel Plate to Air Pressure. would be the greatest air pressure a in. steel plate chamber would resist, and if an atmospheric engine has ever been tried on a railway?—A STOKER. [12419.]-Photography.-Will some one kindly tell me what is the fixing solution for pictures taken on the bichromate of potash and gelatine, or gum mixture; and also describe the whole process, if there is anything at all peculiar in it ?-A. Will any one let me know what [12420.3-American Chucks.-Could you, or some of "our" subscribers to the ENGLISH MECHANIC, give myself and others detail plans of the American scroll chuck, the Warwick chuck, Excelsior chuck, also the Beach chuck? They are extremely expensive to purchase for some of us humble mechanics, and we might possibly make them at our leisure if we had detail plans. Not required to scale; we could make our own proportions. If this request could have attention it would greatly oblige myself and other friends. Could we also be favoured with the mode of cutting the spiral flute on the drills as sold by Buck, &c.?-CHARLES BOWLER [12421.]-Enlarging Photographs.- Can any reader kindly inform me how photographs may be enlarged by the aid of magnesium light ?-INDUSTRIOUS WILL. [12422]-Steam Power.-Would any competent engineer enlighten me on the following:-I have a portable steam engine driving a machine making 1000 revolutions per minute, and I find it very difficult to keep up steam, the engine crank shaft making 140 revolutions per minute, stroke 13in., diameter of cylinder 8 in. Would it be better to introduce a counter shaft with an additional fly-wheel and reduce the speed of engine?-PAT. [12423.]-More Light Wanted. In a range of shops three stories are built along two sides of a piece of ground. How is it possible in a cheap way to give more light to the corners where the shops come together at right angles? The owners of the property adjoining will not allow any windows to overlook them so that there is a considerable space in each shop that cannot be used.-ANTE LUCEM. [12424.]-Preserving Green Peas and Gooseberries-As green peas and gooseberries will soon become plentiful I should be glad if some correspondent would give us the method adopted for preserving them fresh in tins for winter use.-J. N. [12425.]-The Belgian Glass Trade.-Can any reader of the MECHANIC give any information about the Belgian glass trade, when it was established, who by, and where, its present extent, and any other particulars of its history and development ?-E. HOLMES. [12426.]-Piano.-Having purchased a piano a few weeks since, when I got it home and began to practice on it I was surprised to hear a terrible rattling of the wires, which, on examining, I found to proceed from a part of the soundboard having become divided and waved. Could any of my brother readers tell me the cause, and a remedy?-A SUBSCRIBER [12427.]-Entomological.-Can any of your entomological readers tell me of what insect the maggot found in decaying cabbage-leaves is the larva? The maggot can often be found in the mid rib of the lower leaves when they have turned yellow, as it seems to bore its way upwards from the stem, travelling along the natural canals or passages in the substance of the leaf-stem. The same or similar larvæ may be found in other members of the tribe of Brassica when the lower leaves decay. I should like to know what they are, and how they got there.-MIMOSA. [12428.]-Air Vessel for Pump.-How can I ascertain what size to make an air vessel for an ordinary force pump? The pump has a 2in. barrel, and delivers a pint at each stroke, the water being forced out through a valve at the top part of the barrel. Is it immaterial what sized air-chamber is used, so long as it is large enough, or must it be suited to the other dimensions of the pump? If the latter, what is the best material and shape of which to make it? It is wanted to deliver a constant stream through in. rubber hose with in. delivery jet, fitted with tap to regulate the quantity of water.-F. S. [12429.] - An Engineering Inquiry. - I am twenty-one years of age, and have always had a taste for engineering, but unfortunately, never had an opportunity of learning that particular business until now. What would you recommend me to learn so as I may be fitted for a situation as engineer on board a steamer, and also how long should I serve in a foundry or machineshop.-J. A. P. SPENCE. "Flint Jack" Again.-The notorious forger of antiquities (who gives the name of Edward Simpson, of Whitby) has, it appears, being very active of late. He has turned up at Stamford, where it is stated he has been busy manufacturing rings, monastic seals, and flint arrow heads. Mr. A. C. Elliott, of Stamford, has had the man photographed, and intends to circulate copies, that the young collectors may recognise the Labricator on his first visit. CHESS. ALL communications intended for this department to THE "WESTMINSTER PAPERS."-The Westminster Papers is now recognised as the leading exponent of British chess, and for raciness and general ability nothing like it has ever appeared in the periodical literature of the game. None of the affectation of learning and research which characterised most of its predecessors is to be found in its pages; its news is not "ancient history," and its problems and games are neither "curious reprints" nor, as the phrase is, "selected from various sources." Every number contains a summary of the proceedings of the fraternity in all parts of the world during the past month, the latest games of the best English and foreign players, accompanied by judicious notes and instructive analyses, and at least thirteen problems of more than average merit. We may add, although the subjects are out of our province, that the Westminster Papers is also the received authority upon whist, each number containing three or four games from actual play by the finest contemporary whist players in London, besides articles on croquet and other games of skill. PROBLEM VI.-BY HENRY TURTON. White. White to play and mate in two moves. SOLUTION TO PROBLEM V. White. 1. B to K Kt 5 2. B to K 2 8. B or Kt mates acc Black. TO CORRESPONDENTS. E. L. G.-We should like to re-publish the article on mention shall be forwarded. A. W. COOPER.-Problem I. is easy. Problem II. is a W. AIREY.-Problems of more than four moves deep are moves G. SLATER.-Problem I. admits of a solution in two (1) USEFUL AND SOLENTIFIO NOTES. THERE is but little doubt that many broken wheels result from expansion at the hub caused by heated journals. Since the American railroad companies have adopted a strict system of inspection of cars and wheels they have had far less breakage of wheels. Drinking Fountains.-Some information as to the cost of these public conveniences was disclosed at the meeting of the Metropolitan Drinking Fountain and Cattle Trough Association held lately. There are more than 300 troughs and fountains under the care of the society, and all are visited, cleaned, supplied with cnps, and reported at the office every week. The cost of the fountains for repair and water supply averages nearly £10 a year each, but the cost of the cattle troughs varies with their size and locality. The small dog troughs are supplied entirely with the waste water from the fountains, but for the larger troughs the water-rate alone is in some cases as much as £30 per annum, more than 1,200 horses, besides other animals, frequently drinking at one trough in twentyfour hours. A Novelty in the Building Trade.-An Exeter correspondent writes:-"A twenty-roomed house, complete with grates, stoves, and fittings, has just been brought by ship to Exmonth, for transmis sion by rail to North Tawton (North Devon). The house was built in Norway for a gentleman at North Tawton named Vicary. It is mostly built of wood, and, it is said, can easily be taken to pieces and put up again in any locality desired. The house will be unshipped at Exmouth, and conveyed over the London and South Western line to its destination. Great interest is being taken in this novel cargo alike by employers and employed in the building trade. Until, however, the house is put up and inhabited any opinion upon the stability or suitability of the structure must be withheld. It should be stated that men have been brought from Norway to put it up, so that the owner will be altogether independent of home labour." Schools of Art in the Potteries.-The Schools of Art in the Potteries have this year been very successful in the examination of works sent to South Kensington. Hitherto the district has not reached the dignity of a gold medal award, but this year two have been taken-one by Hanley, and the other by Stoke School. The gold medal for Hanley is awarded to Joseph Ellis, for modelling; and that for Stoke to Robert Abraham, for painting from nature. Hanley School also takes two silver medals and three Queen's prizes, and seven pupils have free studentships, besides which the works of twelve students' are selected for national competition. Nearly double the number of students have been successful this year in comparison with last year. Besides the gold medal, Stoke School has been awarded a bronze medal and eight free studentships. In the case of Stoke, also, there is a great increase in prizes over last year. The monetary resulte of the examination to Hanley School are 40 per cent. in advance of last year. Testing Inflammable Oils.-A method of testing petroleum and other inflammable fluids, and also of determining their specific gravity, has been patented in the United States. The apparatus consists of an upright glass cylinder supported in the top of a chamber formed in the upper part of a base or stand. A lamp is placed in the base, the heat from which is transmitted through the chamber to the lower made to contain air, water, &c., as required to regulate part of the glass cylinder, and the chamber may be its intensity. The glass cylinder contains a thermometer, which is fixed therein, and is closed at the top with a brass cover. The burning fluid to be tested is made to completely fill the glass cylinder, so that the thermometer is entirely submerged, and cannot be affected by the surrounding atmosphere. An orifice in the lamp the brass cover is opened to allow the escape of vapour from the fluid ander test, and, when necessary, is lighted. A flame is held over the orifice, and at the moment the evolved vapour is ignited the temperature of the fluid is correctly indicated by the thermometer. In ascertaining specific gravities by this instrument a hydrometer is also placed within the glass cylinder in The other is an interesting composition, and it shall such a manner that its scale tube is free to move up or be published in due course. down through a hole in the brass cover. The surface of the fluid tested is plainly visible through the glass J. P. (Bedford).—The problem in four moves can be cylinder, and the scale may be accurately read. solved thus (4) R mates. R to P G. WHITFIELD and A. L. (Dulwich).-Problems safely to hand. S. M. BANKER.-Your communication not relating to others are wrong. THE "BUILDING NEWS," No. 913, JULY 5, CONTAINS :- Schools; Rev. W. H. Dallinger.-A. S. Lewis.-Mrs. Ethel.-J. T. C. F. C., Holborn Admirer, Young Snip, and J. P. James. E. J.-Not practicable. E. B. J.-See first article this week. JACK OF ALL TRADES has given us a call on his way home after passing upwards of four weeks at Matlock, and a week with "Khoda Bux." He promises a letter for the next number. SIRIUS.-Your letter, as you will see, was superseded by one from Mr. Proctor and one from "E. L. G." ZOO ANDRA.-Your query would be of no service to any one but yourself. E. S.-Yes, it came to hand, and was found unsuitable. PARKER.-Your first query is an advertisement, and your second is only useful to yourself. W. H. FLEET.-We do not know the address, and if we did it would be contrary to our rules to give it you. W. B.-We do not know why Mr. Tonkes is silent. W.WEBLY.-An American publication, and American publications are very frequently echoes of English journals. E. N. H. asks, "Why does not the ENGLISH MECHANIC devote a small portion of its space to legal as well as medical questions? Points of law are continually arising on which light might be thrown by some of our correspondents." JOHN MATTHEWS.-You cannot vulcanise rubber discs after they are manufactured. The soft rubber is mixed with sulphur, and afterwards submitted to heat and pressure-the latter process being the vulcanising. JOHN MANHINNEY.-The data are insufficient to advise apon. You say the wall is "slightly damp" in one place, and in another speak of the "damp spot." If the dampness is confined to a spot it might probably be easily remedied. See Vol. XIV., pp. 313, 337, &c. ANCOATS, T. B., Atlas, E. N. D. (first query), Hoop Iron, W. Watson, A Working B., are referred to back volumes. A POOR MAN.-The method given on p. 386 to mask the taste of castor oil will do very well. Milk, sherry, or lemon-juice are also good. A. C. G.-For music-ruling pens see pp. 50, 104, 159, and 209, Vol. XIV. EXCELSIOR.-We do not understand your third query on Political Economy. Communications which can only appear as advertisements to hand from J. Y., H. Elfes, Drum Maker. E. JOHNSON.It is quite true; the matter has been fully discussed in back volumes. See indices. J. STEABBEN.-See "Hints to Correspondents." G. RICHARDSON.-AEI form the Greek words meaning" For ever." J. GILLAIRD.-Your reply only promises the informatior. but really contains none. If you like to send sketch and details we will insert them. Your other proposal does not seem at all practical, or one likely to be entertained. 195 W. E. Newton, Chancery-lane, for improvemente in the manufacture of vinegar and in the acidulation or treatment of various liquids, and in the apparatus employed therein. A com munication. 1906 W. Phillips, Farndon, Cheshire, for an improved pes IGNORAMUS.-The compass was known and used by the SIMERE SPERENS.-Your suggestion about perpetual R. P. says: "I quite agree with your querist (12329) that a series of good papers on mechanics for beginners would, in these days of science examinations, be very valuable to many of your readers. If some one could do for statics and dynamics what Messrs. Sprague and Bottone are doing for their respective subjects, the usefulness of your paper would be much increased." THE INVENTOR. APPLICATIONS FOR LETTERS PATENT DURING THE WEEK ENDING JULY 2, 1873. traps, and in apparatus for making the same and other curved or 1864 W. E. Newton, Chancery-lane, for improvements in stench partly curved articles. A communication. 1845 W. E. Kochs, Manchester, for improvements in piers, jetties, and landing stages, and in means for effecting the transference of railway trains to and from ferry-boats and floating vessels, and for staying the said trains when on board such boats or vessels. 1866 J. T. Fitzmaurice, Porthpean, Cornwall, for improvements in apparatus for lowering boats. 1867 W. Robertson and J. G. Orchar, Dundee, and M. A. Muir and J. McIlwham, Glasgow, for improvements in apparatus for winding yarn or thread. 1868 G. Maxwell, Lancashire, for improvements in the construction of machinery or apparatus used for making bricks and tiles. heating metals. 1869 T. Davis, Warrington, for improvements in furnaces for artisans. 1870 J. Calvert, Oldham, for an improved lamp for moulders or 1871 I. Fenro and P. Howe, Boston, U.S., for improvements in machines for cutting cloth and other textile or fibrous material. 1872 S. T. Waite, Smith-street, Northampton-square, and J. J. White and J. O. Wise, Bekford-street, Clerkenwell, for the lighting of fires. 1973 G. T. Bousfield, Loughborough-park, Brixton, for improvements in rotary ploughs. A communication. 1874 J. G. Horsey, Broad-wall, Lambeth, for improvements in the manufacture of brushes and brooms, and in the machinery or apparatus employed therein. 1875 E. Turner, Leicester, for improvements in door springs. 1876 S. B. Smith, Birmingham, and J. W. Willans, Middlesbrough, for improvements in the process of and apparatus for smelting iron ores and other ores, and reheating iron and other metals, parts of which improvements may also be applied to other purposes. 1877 G Burge, jun., Rochester. Kent, for improvements in kilns for burning cement, lime, and other substances. 1878 J. Tourre, Avignon, France, for improvements in obtaining colouring matters derivable from madder, manjeet, and other allied roots. 1879 W. Birch, Penrose street, Walworth road, for improvements in the mode of and apparatus for treating horny and other analogous animal substances for the purpose of converting them into for other purposes for which such elastic substance may be applican elastic substance to be used in place of whalebone, bristles, and able. 1880 W. M. Brown, Southampton-buildings, for an improved apparatus for extracting ammonia in the form of liquid ammonia from crude ammoniacal liquors. A communication. 1881 E. Milner, Springfield, Lancashire, for improvements in the method of producing white pigments from lead. 1882 B. Wrigley, Arundel-street, Strand, for improvements in kilns for burning bricks, pottery, and lime. 1883 J. Campbell, Founders-court, City, for improvements in the modes of decreasing the rolling of vessels. 1884 J. Arthur, Sandycroft, Flintshire, for improvements in screw bolts and nuts. 1885 J. Horley, Cheltenham, for an improvement in the manufacture of an explosive compound and a new mode of firing explo sive compounds. 1886 J. Thomas, Middlesbrough, for improvements in furnaces for generating gas and melting metals. 1887 J. Kirby, Preston, for improvements in machinery or apparatus to be used in frames for winding linen or other yarns. 1888 J. Tabor, Leadenhall-street, City. for a mechanical arrangement or "tell tale" for registering the number of packages taken to or from vessels, vehicles, warehouses, and other places. 1889 W. R. Lake, Southampton-buildings, for improved check tickets and methods of forming packages of the same, chiefly designed for use on railways and steamboats. A communication." 1890 L. D. Newell, Aldersgate-street, City, for improvements in ships' berths and sofas. 1891 B. Burleigh, Adelphi-place, Camberwell, for improved lever apparatus for railway switches. 1899 G. A. Dorsett, Rotherhithe, for improvements in obtaining anthracine from heavy oils and in apparatus employed therein. 1893 W. Beale, Bridgwater, for improvements in apparatus for turning over the leaves of music. tiou of desks, sea's, and music stands, applicable to the use of 1894 T. Redmayne, Sheffield, for improvements in the construcschools and other purposes. 1895 J. F. Swinburn, Birmingham, for improvements in breech. loading small arms. 1896 G. Davidson, Aberdeen, for improvements in machinery for washing fibrous pulp or material for the manufacture of paper. 1897 H. P. F. Palmer, Carnarvon, for improvements in cases or crates for containing roofing slates while in transit and other articles requiring packing cases to preserve them from injury. 1898 T. Atkins, Saint Albans. Herts, for improvements in pumps, parts of which improvements are also applicable to other purposes. 1999 P. E. Chappius, Fleet-street, for improvements in the manu facture and application of reflecting surfaces for the better reflection and diffusion of light. 1900 J. Sagar, Leeds, for improvements in machinery or apparatus for raising and foreing water or other fluids. 1901 E Salt, Darwen, Lancashire, for improvements in rag engines, washing engines or beaters employed in the production of pulp or paper "stuff." 1902 E. P. H. Vaughan, F.C.S., Chancery-lane, for improvements in furnaces, stoves, and other apparatus for consuming fuel. A communication. 1909 B. Hunt, Serle street, Lincoln's Inn, for improvements in apparatus for shearing or clipping sheep, horses, and other animals. A communication. 1904 A. Taylor, Stockport, for improvements in apparatus used for bleaching yarns and cloth. 1909 M. Burke, Liverpool, for improvements in screw propeller. 1910 J. Hartley and Z. Sugden, Halifax, Yorkshire, for improvements in boilers for heating of water for warming buildings aud other like uses. 1911 J. L. Norton, Ludgate-hill, and J. H. Carter, Mark-lane, City, for improvements in decorticating, bulling, or polishing wheat and other grain or seed, and in dusting bran, and in ap paratus employed for such purposes. 1912 W. Young, Blandford-square, Middlesex, for improvements in printing and in the production of printing surfaces, also in apparatus to be used for these purposes. 1918 A. M. Clark, Chancery-lane, for an improved distress rudder and drag for vessels. A communication. 1914 J. Townsend, Glasgow, for improvements in furnaces or apparatus for obtaining heat or gases from coal or other substances containing carbon. 1915 W. Harvie, Glasgow, for improvements in lenses and in lamps wherewith such are or may be used. 1916 W. Macrone and W. McKenzie, Glasgow, for improvements in the production of stereotype plates, and in apparatas employed therefor. 1917 S. J. Wallis, Spalding, Lincolnshire, for new or improved mechanism for discharging both locks or barrels of a doublebarrelled gun by one trigger. 1918 W. Sissons and P. P. White, Kingston-upon-Hull, for im provements in steam pile-driving apparatus. 1919 C. W. Siemens. Great George street, Westminster, for Im provements in the means of obtaining and applying magnetoelectric currents, and apparatus therefor. A communication. 1920 C. Caselton and H. Toogood, Hull, for improvements in saw frames or machinery for cutting tile, slate, and other latha, boards, deals, battens, and other woods and materials usually cat by saws. 1921 J. Merrylees, Glasgow, for improvements in weaving ornamental fabrics, and in apparatus therefor. 1922 T. Gibson, Stamford, Lincolnshire, for an improved machine for cutting lump sugar. 1923 J. E. T. Woods, Hammersmith, and J. Clark, Kensington, for an improved alloy for anti-acid metal and for other purposes. 1924 E. G. Brewer, Chancery-lane, for improvements in the modes of and in the means or apparatus for operating the rotating parts of sewing machines and of other analogous machinery. A communication. 1925 R. E. Middleton, Cannon-row, Westminster, for improve. ments in machinery or apparatus for breaking stones, orea, and ether like substances. 1926 R. G. How, Carshalton, for improved mechanism for indicating and recording the speed of railway trains. 1927 W. Corney and S. 8. Turner, Westborough, U.S., for inprovements in stop motion for looms. 1928 P. Poggi, College-street, Chelsea, for an improved mechanical combination, constituting improved motive power machinery adapted for industrial and other purposes. A com munication. 1929 R. W. Simpson, R. Hopps, and D. Johnson, Leeds, for inprovements in machinery for scribbling wool and other fibreas substances. 1980 O. McC. Chamberlain, New York, U.S., for an improved attachment for sewing machines for folding plaits. 1981 J. S. Christopher and J. F. Lackersteen, Lombard-court, City, for improvements in the manufacture of hydrogen gas. 1932 B. F. Stevens, Henrietta-street, Covent garden, for im provements in apparatus for raising, lowering, and securing, ships' boats. A communication. 1933 G. Whitaker and J. Ashworth, Rochdale, for an improved process for preparing wool or other animal fibre for carding a combing. 1934 A. M. Clark, Chancery-lane, for an improved apparatus for feeding and drying whitelead and other pulpy or semi fluid substances, and for feeding oily and pasty substances. A communi. cation. 1995 R. A. Purkis, Cheam, Surrey, for improvements in the moda of and apparatus for refrigerating liquids. 1936 W. H. Denham, Southsea, P. V. Denham, and A. A. Danham Putney, for improvements in water-closets and in apparatus com nected therewith, parts of which improvements are applicable te other purpoвев. 1937 W. R. Lake, Southampton-buildings, for improvements is gathering, ruffing, or plaiting apparatus for sewing machines. A communication. 1938 A. Hookham, Southwark-bridge-road, for improvements in money tills. 1939 M. Paul and J. Haythorn, Dumbarton, N.B., for improve ments in and connected with steering apparatus. 1940 W. Wright, Sheffield, for improvements in taps and spparatus for flushing water-closets, and in taps for other purposes. 1941 J. R. Cazier, North East, U.S., for an improvement in the application of safety valves to steam boilers. 1942 J. W. Ward and J. C. Ronse, Halifax, for improvements in jacquard machinery or apparatus. 1943 J. S. Cooke, Yorkshire, for improvements in machinery or apparatus to be employed in dyeing wool, silk, cotton, fax, or other fibrous substances in the hank or skein, 1944 J. H. Johnson, Lincoln's Inn-fields, for improvements in sifting or bolting machines. A communication. 1945 J Millward, Birmingham, for improvements in hydrants for supplying fire-engines from street mains. A communication. 1946 JG. Tongue, Southampton-buildings, for improvements in the manufacture of artificial flowers, foliage. fruit, and other similar objects or ornaments. A communication. 1947 W. M. Parker and J. R. Robson, Alton, Hants, for improve ments in steam and other motive power engines and pumps. 1948 F. J. Cheesbrough, Liverpool, for improvements in the process of manufacturing oil and oil cake from seeds, and in Re machinery to be used therein. A communication. 1949 J. Fletcher, Lancashire, for, improvements in machinery for forging and riveting. 1950 G. Yule, Wakefield-street, London, for improvements in cylindrical and other rulers for office and general use. 1851 J. H. Johnson, Lincoln's Inn-fields, for improvements in preserving butter and other fatty matters, and in the apparatus means employed therein. A communication. 1952 A. C. Kirk, Glasgow, for improvements in steering ap paratus and in motive power apparatus for working the same, I for working, winding, hoisting, or other apparatus at a dietanon. 1953 H. Giroud, Paris, for a new or improved system of rheometric regulator used with a gas burner only. 1954 8. Chatwood, Bolton, and J. H. Collins, Falmouth, for t provements in separating or dressing tin and other ores. 1955 T. S. Derham and C. W. Thairiwall, Leeds, for improve ments in machinery for manufacturing bricks. 1956 T. H. Phillips, Barbican, City, for an improved apparatus or appliances applicable for heating, cooking, and lighting pur ровен. 1957 W. R. Lake, Southampton-buildings, for improvements in fastenings for uniting and securing the parts of bedsteads and tha other like purposes communication. The English Mechanic AND WORLD OF SCIENCE AND ART. FRIDAY, JULY 19, 1872. ARTICLES. ON SELF-DECEPTION IN OBSERVATION. OST of those who have at any time had occasion to make observations in connection with a strongly entertained theory must have been led to notice the readiness with which the mind lends itself to such a view of observed results as may be most in favour of the observer's theory. When a series of measurements is being made, which should run in a certain way if a certain theory is correct, it will unquestionably run more nearly in that way if the observer looks with favour on the theory than if he is opposed to it. If colour-tests, light-tests, or estimates of shape be in question, then still the predominant theory will exert its influence. No matter how conscientious the observer may be, he finds it almost impossible to avoid falling into an error of the sort, unless in his eagerness to be strictly impartial he avoids Scylla to fall into Charybdis, actually favouring the evidence against his theory rather than do aught in its support not strictly justified by the facts. Let it not be supposed that the self-deception here spoken of is practised only by inferior observers, or that it is of the nature of " a mistake made on purpose." The very best observers have repeatedly found themselves going astray in this particular way; and by their readiness to admit that they have done so have shown that no desire unfairly to advance their theories has been in question. The longer an observer's career has been, the more clearly does he recognise the necessity of watchfulness over himself, unless he can devise some arrangement by which he will be rendered unconscious of the bearing of his observations on his theories. The worst of the matter is, that observations ought to be made in subservience to some theory, since otherwise they will almost certainly be wanting in precision and system. The best observations ever yet made bave been conducted in connection with theory, and in every instance where observations have been made by those who instances which seem to throw light on the subject In the first place, I will cite a series of instances It is well known that the family and school of Cassini maintained that the polar diameter of the earth is longer than the equatorial diameter, while Newton and his followers maintained the contrary opinion.* Originally, Cassini had believed the earth to be oblate, and from a passage in the article," Figure de la Terre," by D'Alembert, in the original "Encyclopédie," it appears that Cassini inferred that in consequence of this oblateness the length of a degree would decrease from the equator to the pole. Starting with this erroneous assumption, the school of Cassini "arrived at the same result by observation and measurement." nition of the phenomena which should make their appearance if the theory were true. Far away, to the west of Dr. Oudemans, was stationed Mr. Lockyer, at Baicall. To him the theory still remained dear, that the corona is, in the main, a phenomenon of our atmosphere. What were the particular appearances which he expected to see in demonstration of this hypothesis deponent sayeth not-probably we shall never know. But that he did expect to see such appearances-nay, that whatever they were he did actually see them, will appear in the sequel. At Baicull, also, and at Dodabetta, 8,000ft. above the sea-level, were stationed certain inanimate, but very efficient, observers, who were certainly not prepossessed in favour of any theory, and who possessed to a very remarkable extent that quality which has been called by Doré "collodion in the eye" I refer to the photographic apparatus set up by Mr. Davis at Baicull, and by Col. Tennant at Dodabetta. The moon's shadow came and went, and the observers, animate and inanimate, did their work; the results are most instructive. The totality was scarcely over when there went forth from Mr. Lockyer, at Baicull, to the observers at Jaffna (just preparing for totality) this startling telegraphic message, "The corona is almost wholly an atmospheric phenomenon." In some unknown way the atmospheric glare theory which had possession of his mind cansed the observed appearances to seem demonstrative of its correctness. Dr. Oudemans, in the east, was similarly My obfavoured. He writes to Mr. Lockyer, servations and those of my party" (inoculated, we may fairly imagine, with the lunar theory)" have given me the conviction of the existence of an optical phenomenon besides the purely solar phenomena; not of an atmospheric origin (there is no question whatever of this), but of rays variable during the totality, too variable to be attributed to solar matter emerging from the body of the sun itself. I could follow the rays and rifts as When it was shown that the assumption was erroneous the Cassinians maintained the accuracy of their observations, and thus necessarily adopted the theory that the earth is a prolate spheroid, the polar axis being the greatest diameter. But "there can be no doubt," says Mr. Todhunter," that at least Maupertius and Clairaut, who were the most eminent of the French party sent to measure the Lapland arc in 1736, "held the correct Newtonian theory as to the figure of the earth; and their result was rather too decided in its confirmation of this theory. Now the geodetical angles could scarcely be influenced by the opinions of the observers, because it would not be obvious in what way the result would be affected by an error in the angle. But on measuring the base it would of course be obvious that the larger was the value obtained the stronger was the evidence for the oblate form. Similarly, in estimating the amplitude of the arc, the smaller the value obtained the stronger was the evidence for an oblate form. In these two parts of the survey, then, it would be necessary to be on the watch lest the conviction of what the result ought to be should influence the impression of what the observation really gives. It is curious that Maupertius and his far as the moon's edge." party seem to have thought at first that their thus so completely demonstrated themselves and success was too decided, and, therefore, their amplitude too small, and that on their second disposed of each other! the inanimate photographic determination they should have made it between observers had been at work, and had done their three and four seconds larger than at first." work in such a way as to dispose of both the rival theories at once. At each station five photoSvanberg was sent to Lapland with a strong expectation that he would obtain a less value of graphs had been taken (not counting one imperfect one at Dodabetta). Each photograph of a degree of the meridian than that of Maupertius; each set shows a multitude of rays and rifts very and according to the best estimates of the value of a degree for the part of Lapland where the peculiar in form. I suppose that upwards of a arc was measured, Svanberg's value was below the hundred well-marked features can be counted in each picture. These features are absolutely true value. identical in all the five pictures of either set. The pictures of one set are absolutely identical with But alas for the rival theories which had boast that they have no theory at all on the sub- observations of last December afforded yet more those of the other set. Comparing the pictures ject under observation, the results have been of little value. Indeed, I may notice in passing, that those make a great mistake who attach exceptional weight to observations made by persons who have no special views on the subject of observation. Though the object of this paper is to dwell upon the errors made by observers strongly prepossessed in favour of a particular theory, I should be sorry indeed to seem to give any support to the notion that the best observations will be made by persons having no theory at all. To say that a person has no theory at all on a subject, is to say that either he knows very little about the subject, or that he has no brains worth mentioning. No man who has a respectable supply of reasoning faculties can fail to form opinions as the facts relating to any subject are brought to his knowledge. It would, indeed, be very unwise for him to arrive at conclusions at an early stage of his study of the subject. He should be prepared to modify his opinions; and he may regard hereafter as unlikely the views which he had at first entertained as probable. But we may be well assured that one who forms no opinions as his study of a subject proceeds, who is not ready to form hypotheses explanatory of the facts brought to his knowledge, who is continually waiting to know more before entertaining any theory at all, will never have an opinion worth listening to. Not only is it true, to use Sir W. Herschel's words, that to observe without theorising is to "depart from the very purpose for which observations are made," but the observations themselves suffer when they are carried out in so purposeless a way. My object, then, is to indicate the necessity for the devisal of methods for freeing the mind from the influence of preconceived opinions, not, assuredly, to advocate such an avoidance of theory as can only be attained by the weak-minded. It is for the former purpose that I adduce some Striking as are these facts, however, the eclipse remarkable evidence of the self-deception which may arise from the effect of a preconceived opinion. It may be remembered that Dr. Ondemans had expressed the opinion that the solar corona is due to the illumination of matter close by the moon. This theory is mathematically defensible so far as the shapes of the coronal rays and rifts are concerned, if only certain phenomena are observed during totality. It is perfectly clear, since the theory explains the rays and rifts as due to the passage of the solar rays past valleys and mountains on the moon's limb, that as the moon passes athwart the sun's face the rays and rifts should change in position, shape, length, and so on. Now, as a matter of fact, the evidence obtained during the eclipse of December, 1870, had completely disposed of Oudemans' theory. It is perfectly well known that the doubts expressed as to the agreement between the photographs taken by Willard, at Xerez, and by Brothers, at Syracuse, were based on imperfect drawings of these photographs, and though these doubts were not ostensibly withdrawn, the photographs themselves completely disposed of them. But to Oudemans, at Batavia, this news did not penetrate. He set forth to view the total eclipse of last December with unshaken faith in his lunar cosmical dust theory, and with a perfectly clear recog * I quote from a most valuable paper, by Mr. Todhunter, "On the Arc of the Meridian Measured in and Transactions of the Cambridge Philosophical Society, Vol. XII., Part I. It is completely answered, I conceive, by the objections I have urged against it on account of the smallness of the total quantity of light which would be received from the region in question, as compared with the quantity received-according to the theory itself when all its consequences are considered-from matter beyond the moon. I submitted this objection to Sir John Herschel, and in his reply he expressed his perfect agreement with what I had urged on the subject. of either set of five, we see the moon measurably traversing the corona as the eclipse progressed, thus definitively disposing of the lunar theory ;* while, comparing the two sets, we find the features photographed at Baicull, on the west coast of India, close by the sea-level, absolutely identical with those photographed at Dodabetta, on the Neilgherries, 8,000ft. above the level-thus definitively disposing of the atmospheric theory. In passing, it may be remarked that perhaps it was a little hard of Mr. Lockyer to publish the parts of Dr. Oudemans' letter which relate to the Oudemans wrote in lunar theory of the corona. complete unconsciousness of the photographic evidence which has been so long in the hands of European men of science; had he heard of the photographs he would doubtless have wished to withdraw his remarks on the lunar hypothesis. Still, the lesson derived from these matters is so Dr. De La Rue (once, by the way, an advocate of Oudemann's theory) informs me that in Col. Tennant's negative the features of the corona can be seen (and identified in the several pictures) to a distance of one and one-seventh diameters of the sun. In Lord Lindsay's series, the negatives of which I have had the pleasure of examining, with oxyhydrogen illumination, precisely as set for the engraver to work from, the features can be traced very nearly as far. They are not by any means mere straight rifts or rays, but of most remarkable figure, here a short spiky projection, there an irregularly-shaped obelisk of light, in another place a long ray of double curvature, in yet another a complicated knot of streaks-altogether the most marvellous astronomical picture my eyes have yet rested on. Janssen's description, with its marked reference to "special shapes altogether irreconcileable with an atmospheric theory," is strongly recalled and fully justified. Yet the photographs show but a portion of the extension of these strange figures. observer, Capt. Tapman, who drew a capital picture of the corona, agreeing well with the photographs, could trace these features much farther. That excellent By the way, when are the reports of the eclipse expedition to be available for study? What occult caus is preventing us from hearing what was done? |