308

OLD MUSIC.

ing an old file of the Times, Chronicle, Post, Herald, I have found this to be the case two or three times sitting down to his organ or piano, was asked to play

The Polytechnic advertisements and notices of the ammer of 1846, which may easily be seen by consultSun, &c., &c. I may also appeal to the testimony of umbers who attended my lectures, and I think I may say further, that there is scarcely a living electrician of note, who did not witness my experiments. I feel bound to say in conclusion, that I am convinced Mr. not cognisant of the facts above quoted. I merely

Sir,-1f one of your "Harmonious" correspondents, not pressed firmly down, the hinge goes behind the the oldest tune in the world; what tune would it be? end of the shuttle reel and shuts it out, instead of in. tune. Why not? The Englishman is often too ready with persons I have sold machines to. I think Howe's think those represented on page 157 are quite as good Let me suggest that it would have to be a Welsh I have had and worked a to sneer at Wales and Welsherie. But, there wer shuttle admirable for leather or heavy work, but My opinion respecting the pause Welsh bards; they had music, harps and all: much for general purposes. machine 10 years. but in my machine the needle bar goes down to the

Hearder has acted entirely under a mistake, and was spoken of by "Study," on page 211, is, that it is good, of their music has come down to our scoffing age; speak to settle the question of my original discovery full extent, then comes up a little way (thus making some of it must be old, and I want to know whether The air, indeed, is said by the English tourist, Bingley. Cruly glad to perceive that Mr. Hearder, whose general again just as the shoulder of shuttle is passing Take one tune, by no means the most ancient-"Morfa over the thick part of shuttle, and finally the needle in the year A.D. 801; more than a thousand years ago. to be infinitely too artificial for those dark ages; electrical experience is well understood, is bringing through the loop, and, as it were, eases the thread Rhyddlan." It commemorates a battle which occurred bar comes up, immediately the shuttle is past the but, does not this viciously beg the whole question, GROCER. needle, to tighten the stitch. Is his the same? whether those ages were "dark" in the sense of musi cal skill? Also, the tune, as a plaintive elegy, bewailing, a local slaughter, would not have been likely to be composed except at a time when feelings were fresh. To doubt the date, seems to be mere doubt for doubt

is researches to bear upon so prolific and so interest-
ng a field of physical investigation.
ISHAM BAGGS.

PITMAN'S PHONOGRAPHY.

SIR, Will you allow me to inform "Hermit," page 55, that there can be no doubt whatever that Pitman's Phonography is the best system of shorthand. It is

AN IMPROVED TRICYCLE.

SIR. I have enclosed an elevation of a tricythe more than the three wheels and the smallest possible the English Dr. Burney doubts whether the Welsh which I have been altering and simplifying for the ounded on philosophical principles, and its alphabet last twelvemonths until I have reduced it to little ings sake, and as gratuitous scepticsm, as when again Lains a symbol for each simple and distinct sound in amount of framing. I can do ten miles an hour on a point is found in full force in the Welsh manuscript

down hill, and more on a level road. There are india-
rubber tires (of a good substance) on all the wheels.
road composed of the average amount of up and
The front wheel is the driving and steering wheel, and
In designing a tricycle, there are certain points to be
benefit of them. The first is, to keep the seat well
experience, and now offer my brother readers the
down between the hind wheels, so as to employ the
forward thrust of the foot instead of the downward
The second is to proportion the
pressure, as is usual.

could have invented counterpoint; and yet counterLet me select as what I conceive to be Beroriaeth.

rest of the old Welsh tunes, the beautiful and really sacred air" Nos Galen." It has strange antito by one of the greatest and most indubitable of the bards. This bard was Aneurin; he flourished A.D. in a perfect state; it is highly epic in its tone, and is

the latter to a beginner. In comparing phonography nothing can exceed it for easy and luxurious riding. que grace, and a fine flow of melody; and it is alluded say that it is easier to learn, easier to write, and. observed to insure success; I have found them out by 570; his poem "The Gododin" has come down to us

ay truly be called the alphabet of nature, as it congenerally be found to be persons advanced in life; our language. Those who write other systems will who learned shorthand before Pitman's system was introduced, and I feel sure they would all recommend with other methods of shorthand, it is sufficient to what is almost of greater importance, easier to read. In fact, I may safely say, that phonography is the only kind of shorthand which, when put into actual practice, and written with any degree of speed, can be read with perfect accuracy by any one else besides the writer. It is no uncommon thing for verbatim reports of speeches, taken in phonography, to be sent to the compositor without any further transcribing. I think it needless to occupy one or two columns of Our valuable space in dilating on the advantages of "Hermit" will find an essay on the subshorthand. ject at the commencement of any treatise on the art, if his common sense has not already suggested them to his mind. Suffice to say, that it is a great mistake to suppose the art is only useful to reporters; perBons in every situation of life would find a knowledge of shorthand of the greatest use to them; they would find time and labour saved to a very great extent. Phonography can be written at a speed three times that of ordinary writing with scarcely any muscular fatigue, and the shorthand writer can keep it up for about half an hour without any intermission, whereas a longhand writer, if he writes at the top of his speed, is dead beat in a very much shorter time. With regard to the length of time taken to acquire a knowledge of shorthand, nothing definite can be said. Some people will learn as much in a month as others will in a year. I have had some experience with shorthand classes, and I have found that while, as in everything else, only a few attain to real excellency, yet all are able easily to comprehend the simple and very beautiful principles of phonography, and by a moderate negree of bona fide application, to acquire a fair knowledge of the art in less I have known a person without any than a year. previous acquaintance of phonography, write with very great accuracy in six weeks' time. This of course is an exception. It will generally be found that a moderate amount of daily application will enable anyone to write phonography at the same rate of speed at which he writes long hand in, from two to six months' time, varying, of course, according to the

distance from the seat to the treadles to the length of
the intended rider's leg. The third is, not to put more
weight on the driving wheel than is absolutely neces-
sary to keep it to its work; that is to say, to prevent
its slipping: and last, but not least, to have good
indiarubber tires to all the wheels, but especially to
the driver. My front wheel is 30in. in diam., and the
trailing wheels 36in.; the reach is composed of two
pieces of ash, bolted together at the front, and sepa-
rated about 6in. at the back with a square mortice
through each, through which a piece 2in. square, passes

unmistakeably primitive in its grandeur, if and is longed to any other country but the Wales which the Prince of Wales never goes near, all our English glossographers and antiquity-mongers would rave about it. This Gododin poem of Aneurin has been ably edited, word for word, and translated by Williams. At line 884, are the granitic old Welsh words, " Cann calan a darmeithei," meaning which he wove into a song for the calends of January. Thus this is a direct recognition of the air Nos Galen-Nos is night, and Galen or calan is calends; Nos Galen is Christmastide; and why do not our British churches use this oldest of Christmas carols? I fancy "Rousseau's Dream" is a mere adaptation of it. Will some friend adduce a tune older than this "Nos Galen," which is 1300 years old?

GIMEL.

DRY PLATE PHOTOGRAPHY. SIR,-Different systems seem to succeed with different manipulators. For my own part, I could make nothing of tannie acid, and little of collodio-albumen, but I succeeded well with Fothergill's process. My method was as follows:-Sensitise as usual; wash in six drachms of distilled water; pour albumen over the plate, and let it run well over the surface backwards and forwards for nearly one minute; wash in three waters, and let the plate stand to dry; develop with pyrogallic. I used Keene's collodion, and

need of the black varnish, as the film was perfectly

blisters, or anything of the sort. nd never found

secure.

This is a more troublesome process than "Tannic

M. W. G. INTERFERENCE RINGS ROUND THE SUN. SIR,-On page 265 of the present volume, in the last

Acid's" and consequently his is preferable on that account, if the result is as good. Perhaps he will try this, and I will try his, when I can."

ability of the learner, and the amount of time he gives to carry two iron arms for the back wheels; the seat is paragraph but one of Mr. Webb's "Hints to Astroup to it. Further practice increases both the speed centered between the two pieces of the reach, and sup- nomical Students," he says respecting interference

no iron

ported on a spring at the back; there are
tyres on the wheels, which makes a considerable
difference in the weight-it weighs altogether 701b.
Mr. Shipton, page 253, has a good deal to learn in
the matter of velocipedes; he has too many levers
about his machine. He will soon find that working
him.

and the ease of writing. Expert verbatim reporting can only be acquired by years of constant practice, "How many years ?" I think and if "Hermit" says, I might say, that if you are naturally clever, and take a liking to the thing, and work hard at it, you may a speaker at the end of two years' time. It is impos- his arms and legs (spider fashion) will soon exhaust enable him to see the interference rings round the sun perhaps be able to follow very closely on the heels of

sible to say how long it would take to be able to follow a very rapid speaker verbatim. My own opinion is there are not half a dozen men in England who can do it.

The spread of phonography has been very much retarded by the constant changes-I ought rather to say improvements-which Mr. Pitman has from time to time had the honesty to introduce into the system, to the detriment of his own pocket and the vexation of old phonographers. I am, however, happy to say, that a great deal of time and labour, has lately been expended in bringing the system as near to perfection as it is possible so to de, and phonography, according to the 18th edition of the "Manual," which will, believe, shortly be published, is likely to remain, for the future, substantially the same. These changes are of course only on minor points, and do not at all affect the general principles of the art, nor do they in any way deter anyone from making use of the exist All needful books can be obtained from Mr. Isaac Pitman, Bath, and the Phonetic Journal, published weekly, contains a list of persons who correct exer

ing edition of the " Manual."

cises sent through the post, gratuitously.

SEWING MACHINES.

W.

SIR,-If you think the following remarks will be of any use, you may insert them in your next notice of sewing machines.

sented, on page 157, as coming off the shuttle from the
In your impression of May 6th the cotton is repre-
top, whereas I find from experience it comes off easier
Let anyone who
and more regular from the bottom.
has a machine try for himself. In Fig. 10, on same
page (if your instructions are intended for anyone to
make one for himself) the spring should be made long
enough to catch the brass end of shuttle reel, and it
only wants to be just enough of a spring to keep the
reel from turning after the tension in making the
stitch ceases. I think the method of keeping the reel
in shuttle as represented in Fig. 8 is preferable to
No, 9 with a hinge at the end, because if the reel is

medicine."

SINGING.

T. COOKE.

undoubtedly due to such a cause, and in all Vegas have noticed a border round the limb of probability it would be very conspicuous round the dages." I think an experiment I have tried will sun were it possible to view him without such a dark very easily, and also possibly lead him to suspect that ening apparatus as must extinguish all such appen such an appearance in optical instruments arises, not from the passage of light through space, but from the character of the media we employ. I took a simple pocket lens and placed it in the sun, then stood about a yard off. The lens was about an inch focus. The image of the sun in this position resembles a brilliant star. I then took a narrow slip of card, and with a pin pierced a small hole; then about half an inch of the pin or with a small ueedle; a fourth was made from this I made a smaller hole. Then, at the same distance, a third, pricked with either only the point still finer. Now, on looking through the first hole, held close to the eye, the interference rings were plainly perceptible, but through the second still more apparent, and the spurious disc of the sun larger; in very fine hole the disc is larger still, with only two or the third hole the disc appears larger still, and in a three interference rings. I tried the experiment also with a hemispherical lens, with rather a better result. It was a very interesting experiment, and the view of the minute image of the sun resembled a very distinct scope. Now, on making the experiment at night with image of a brilliant star as seen through a good telethe same instruments, only using a paraffin lamp for the source of light, I found exactly the same effect produced, where, of course, the effect of distance could not be taken into account.

SIR, AS so many in your columns have been afforded opportunities for the consideration of musical instruments, I feel sure of a little corner for a few words from an old author on the cultivation of the voice. Singing is not only the expression, but an aid to the acquirements of the "merry heart," which, as Solomon tells us, "maketh a cheerful countenance," "hath a continual feast," and "doeth good like a William Bryde, one of the greatest musicians of the Elizabethan age, in the preface to his collection of Psalms, Sonuets, and Songs of Sadness and Pietie," published in 1598, gives the following reasons for learning to sing, the amusing quaintness of which is mingled with good sense:- Reasons brieflie set down by th' auctor to persuade every one to learn 1. It is knowledge easilie taught and to sing. quicklie learned, when there is a good master and apt scholar. 2. The exercise of singing is delightful to nature, and good to preserve the health of man. 3. It doth strengthen all the parts of the heart, and doth open the pipes. 4. It is a singular good remedy for a stuttering and stammering in the speech. 5. It is the best means to preserve a perfect pronunciation, 6. It is the only way to THE EYE.-INVERTED PICTURES. and to make a good orator. know where nature hath bestowed the benefit of a good voice, which gift is so rare, that there is not one SIR, Our friend and instructor, "F.R.A.S.," page that excellent gift is lost, because they want art to 277, justly answers" The Welsh Shepherd" as to inamongst a thousand that hath it; and in manie, express nature. 7. There is not any musick of instru-verted images." When the top and the bottom of the ments whatsoever comparable to that which is made of the voyce of men, where the voyces are good and the same well sorted and ordered. 8. The better the voyce is, the meter it is to honour and serve God therewith, and the voyce of man is chiefly to be employed to that end."

"Since singing is so good a thing.
I wish all men would learn to sing."
G. R. LUFF.

W. C. M.

the picture upon the retina will affect our judgments
as to the real position of visible objects. The "W.S."
mind is determined we shall find that the position of
around him in an inverted position (as "W. S.
presumes) that he would see his own drawings in the
appears to forget that if the little boy saw everything
same manner, and therefore represent them in the
same position as a normal eye sees them.
YOUNG IDEA.

EXAMINATION QUESTIONS. SIR,-In his letter, on page 282, by taking the volume of one gramme of hydrogen as 11-16 litres, instead of using the more accurate value of 11-161, Mr. Davis makes the answer to "Zeta's" query 101 454 litres, instead of the more correct volume of 101-461 litres. This discrepancy between "Zeta's" replies might confuse him, so I have referred to it to explain how the difference arose. In answering such questions as this a certain degree of accuracy is essential, and it is to be regretted it is not always used. Also with regard to methyl, Mr. Davis has assumed the theoretical specific gravity 10365; Frankland and Kolbe's researches, though, indicate a specific gravity considerably higher, approaching that of ethyl hydride -that is to say, about 1.075.

Allow me to draw the attention of "Sigma" to the letters on page 283, signed by Mr. Kernan and " E. J. W." The latter is especially rich, and its author seems to hold a very different idea of the "safety and security" of the South American Republics to that of Her Majesty's Government, or perhaps I should qualify by saying he "believes."

For" acids,"line 10, page 282, read "oxide."

THE FLUTE.

URBAN.

EXTRACTS FROM CORRESPONDENCE.

correc

REPLIES TO QUERIES.

LITH ARGE AND GLYCERINE CEMENT. -I am sorry to say that in my hands this has proved a total failure. A very valuable cement, which I have used for many years, and which is especially serviceable where cavities have to be filled, is made by mixing equal parts of litharge and white lead with a sufficient quantity of copal oil varnish. Of course it should be only made as wanted.-T. W. WEBB. [2734.]-THE GOAT AND THE GRASS PLOT. - In answer to Captain Baxter's query, I beg to inform him that the length of tether required would be 23 ft.-G. A. S. [3490.]-THREE-WHEELED VELOCE.-Should key ou one wheel on the hind axle, and leave the other to run loose: it turns corners, drives as well as with ratchets, and is economical. I have made one.-J. H.

REV. E. KERNAN'S "SERIOUS ERRORS.""Inertia" writes :-"On page 257, of our journal, Mr. O'Connor has attempted to correct serious errors in the very useful and instructive papers written by Mr. Kernan, occasionally given by you, and doubtless read by the majority of your readers with great pleasure and satisfaction; for my own part, they recall old lessons and laws (sometimes nearly lost in a practical life) with a freshness and simplicity so readable, that few of us will finish the chapters without some benefit, even if it but refreshes the memory of rudiments too often forgotten. Surely the presumption so visible in one that has yet to learn the correct meaning of inertia and momentum, will meet with the remarks from your better informed correspondents they deserve. Allow me to observe, Sir, that this one incorrect" tion,' forms the "few errors so ostensibly displayed by your correspondent. With regard to the classification, if Mr. O'Connor will read the former paragraphs in connection with the one he has quoted, I think most of your readers will form their own conclusions as to the one which is so much superior' to the other." EMIGRATION.-R. Smith writes:-"I am very [3779.]-BOILER AND SAFETY VALVES.-I beg to glad to see the emigration question in your pages, and answer this very important question more fully, for the I cannot but think, an amount of useful information benefit of amateurs and others requiring to know the pressure will be obtained by its ventilation. I have travelled on safety valves, or weight on lever to equal a given pressure in the United States, and will answer with pleasure of steam on valves. First find the weight of valve D, spindle, any inquiry from brother readers. I think there is great hope for "Railway Clerk" in the Western States, where he could tickle the earth with greater advantages to himself and family, than ledger tickling in railway depots in England.

SIR,-As flautists are coming to the front in the correspondence pages of our magazine, perhaps I may be allowed a few words. An eminent composer when asked why he wrote so little for the flute in the scores of his operas, replied that he hated flutes-they were never in tune. This has remained a fact in flutes up to a few years back. I have been in the musical profession as a flautist for a number of years. I began with the old Nicholson flute; and however well it may be made, it is a most imperfect instrument. There are always some of the notes a great deal weaker than the others, especially C and E, and the instrument is generally more or less out of tune, defects arising from the holes not being in their proper position. If they were so, the fingers could not reach them. In the flutes (Siccama Patent) sold by Chappel, Now Bond-street, it is sought to remedy this by the introduction of a key for the third finger of each hand by making the holes and bore of the instrument larger. They are very good instruments. The flutes sold by Boosey (Pratten's Perfected) are also very good, but neither of them attain to what is wanted-equality of tone and tune. I played some years on the Boehm Flute, and although the change of fingering involves the student in an extra amount of practice, I feel assured that in the end, from increased tone, correct tune, and ease of execution, he will congratulate himself on having adopted the Boehm system. A recent correspondent speaks of the constantly-recurring dificulty in executing rapid passages on this flute. This is directly contrary to my experience. With the old system of fingering it is impossible to execute in a creditable manner many slurring passages in extreme keys; they are simply botched and struggled With the Boehm Flute it is about as easy to play on five or six flats as to play on that of C natural. The flute I use at present is Carte's patent, combining Boehm's fingering with Carte's fingering and improvements. For volume and quality of toue and facility of fingering, I believe they are unequalled. And for the great desideratum in flutes-that of being well in tune-I can almost say, using the words literally, they are perfect. The only objection I have to thein is their price-to the profession £22. Before purchasing this instrument I was induced to read Clinton's essay on his flute, and naturally thought great things of his instrument. I made inquiry of some flautists who have held good positions in London. I was told his flute was gradually being abandoned, and that the Carte-Boehm is adopted by the principal players in the profession; personally I know nothing of it.

over.

ORION.

THE BICYCLE.-J. Hare writes:-"A correspondent of yours, who signs himself N. G. Lamborne, and who states he has been a velocipedist more than twenty years, states, The bicyele is only fit for those who are fond of dangerous sports. Now I think this rather too hard on us poor bicyclists, and beg (to inform him, that I, a mere amateur, have performed several journeys on both business and pleasure, on this dangerous' (?) machine, carrying a considera ble weight of luggage on my last journey, and did it all without a scratch. I think the bicycle, made as light as possible, consistent with the required strength, with a few minor improvements, and a pair of the india-rubber tired Phantom' wheels, will be the machine of the future. Yet I, along with many of your correspondents, should like to see the merits of the different machines ably discussed in your journal. I must, however say, that I have not tried these celebrated wheels, mine being a machine with a pair of tages which the advertisement states, they must be first-class ash wheels, but if they have half the advanindeed a great desideratum to admirers of the bicycle." COMMERCE AND TRADE.-"A. W. J." writes: -"Your correspondent, F. W. M.,' seems to have got into quite a mist; he has been firing wide of the mark, he is discussing a point that 'Herbert' never raised. I consider Herbert's' argument is conclusive. 'Herbert' says, 'If I freight a ship with a cargo which costs me £18,000, and she brings me back a cargo in lieu of it, of the value of £29,000, I think my trade would be very prosperous,' &c. Let F. W. M.' read this again and then his own mystified reply. Again, let F. W. M.' send a cargo, worth £10,000, and in return receive only £9,000; methinks he would soon have to retire on a beggarly nothing. His argument as regards paying workmen's wages, is very childish. I should judge from his note, he is not a business man, nor either that he is acquainted with the laws of trade."

TURNING HORSESOUT TO GRASS.-" C. E. S." in a letter says:-" When horses have suffered in their work from anything of the nature of strain of the sinews or their ligaments, or when their legs are very much the worse for wear, they should be allowed no exercise but such as they can get in a loose box; they should be treated as a man would be who had sprained his ankle and must be confined to his sofa. On the other hand, I have seen horses which were pretty good on their legs, but stale, groggy, and tucked up from hard work and dry and exciting food, improve as if by magic when turned out to grass on the following plan. I have housed them during the day time in a well-ventilated building, darkened so as to exclude the sun and flies, giving them about half a peck of corn daily, with bran and clover chaff; they have then been turned out at night in a pasture in which there was an abundance of grass. Under these circumstances they are never tormented by flies, when they are out all is cool and quiet, the long grass saturated with dew supplies an admirable, cool, refrigerating poultice to their legs and feet, and the grass they get, combined with their daily feed of corn, seems to plump up their bodies withont much interfering with their condition for work. I have taken up horses treated in this way as late as September, and had them in a very fair order for work by the commencement of the hunting season."

USES OF VINE LEAVES,-A correspondent of the "Philosophical Magazine" states that from experiments which he has made he finds that, on being dried. which should be done in the shade, and infused in a tea-pot, the leaves of the vine make an excellent substitute for tea. He has also found that, on being cut small, bruised, and put into a vat or mashing tub, and boiling water poured on them in the same way as done with malt, the prunings of the vine produce liquor of a fine vinous quality, which, on being fermented, makes a very fine beverage, either strong or weak, as you please; and, on being distilled, produces an excellent spirit, of the nature of brandy. In the course of his experiments he found that the fermented liquor from the prunings. particularly the tendrils, when allowed to pass the viuous, and to run into the acetous fermentation, makes uucommonly fine vinegar

[3773.]--PLATE PHOTO CAMERA.-I beg to inform "Mus." it is a camera for the studio that I wish to construct first, but hope he will at some future time give sketch and description of a portable one, as I have no doubt many other eaders of the ENGLISH MECHANIC would be benefited thereby.-SNATCH BLOCK.

A PRACTICAL METHOD OF DETERMINING
THE FOCAL LENGTH OF A CONCAVE LENS.
"S. T. Preston," writes:-" Place the lens in the sun's
rays, so that the luminous circle, formed on the screen
is equal to twice the aperture of the lens; then the
distance from the screen is the focal length required.
Or combining with the lens, a convex lens of short focal
the focal length of the combination, and calling F the
length, whose focal distance is known, then observe
focal length of the lenses combined, and f' that of the
convex lens, the required focus may be simply got by
the formula,
Ff
f-F

Required focus =

NUMISMATICS.-Samuel Smith writes:-" I trust that Mr. Henfrey will accept my thanks for his reply to my query about the two coins, as also Collector, who has quite destroyed my belief in the Immanuel de Rohan being a token. I am obliged to him for doing so. I am interested in Mr. Henfrey's articles on ancient coins. I hope, when he comes to treat on the gold coins of England, he will drive away some of the mist that hangs over them, and explain how a noble, which nearly equals our sovereign in weight, and exceeds it in beef buying capabilities twenty times, should be called 68. 8d. It was valued at 80 pennies, but the penny was a very different coin from our present coin of that name. I fancy an article on that subject would interest a good many readers."

Then

and lever, and add to it the weight of counterpoise weight
required to bring the lever to a level in lbs. and ozs.
find the pressure you want on valve, or by knowing the
pressure you want on the square inch; multiply this pressure
by the number of square inches of valve surface, or rather
then from the pressure on valve found subtract the weight of
outlet, as at E, and the product is the pressure on valve;
valve, spindle, lever, and counterpoise weight, and multiply
by the length in inches you want the weight to be towards C,
this product by the length in inches from A to B, and divide
and the product is the number of lbs. weight to be hung on
the fixed point at C. Example: Say lever 23 in. long, and
valve, spindle, lever, and counterpoise weight weighs 1lb.
10oz., valve 3" diameter, and 60lb. pressure per square inch,
7.0686 x 60 = 424-1160 14625 419-4910 x 3.25 =
1863 345750 23-25
23 in. from A. Multiply the square of the diameter of valve
=58 64lb. weight required at C.
by 7854, and the product is the area of surface 3" x 8" =
9 x 78547-0686 square inches in Sin. diameter. Divide
the number of ozs. by 16, the ozs. per lb, and the product is
the decimal value of the ozs., 10-00016625 =
10oz.-J. HOVELL.

BOILER INSPECTION.-John Swift writes :your very numerous readers in the engineering world "Might I be allowed to draw your attention, and that of to the fact of a select committee of the House of Commons now sitting to inquire into the causes of boiler explosions, also to remark as to the personnel of said committee, that nine out of the fifteen gentlemen are all Lancashire manufacturers, and I think two others also engaged in trade. That there are no working men's members on the committee, but that there are two members for Bolton and no member for Birmingham. The county of Staffordshire, I think, is distinguished for boiler explosions, but Mr. McLean's namelis not on the committee."

VELOCIPEDES.-S. James says:-"In reply to 'Isle of Ely, the oscillating treadle bars of the back-wheel bicycles are 10in. apart only, and the chains never rub the wheel in ordinary turnings. When they do it makes no difference. I think he does not understand the treading motion. It is not an uncommon one, but the same as that in the Macclesfield,' Edinburgh, English,' and all the improved tricycles."

[3803.]-CHANGING THE COLOUR OF PRIMROSES.IfJ. D. M." wishes to permanently improve his primroses, and to obtain a good race of his own ennobling, I would recommend him to cross-breed them with dark coloured polyanthus, and to save and sow the seeds. likely be seedlings of various colours; he can save those he The result will most likes best, and if he chooses repeat the process of crossbreeding them at pleaeure, till he obtains a race which will amply repay him for the slight attention required. I think he will find this a much safer and more interesting method than using chemicals. If "J. D. M." is not familiar with our Editor's permission) endeavour to give him a few. If he hybridising, and would like to have a few hints, I will (with merely wishes to improve those he already has, high cultivation may perhaps do this.-S. ROGERS.

[3839.]-TRACING CLOTH.-Get a 6d. pot of ox-gall. and mix a little both with ink and colours; if ink won't, then take on the cloth, increase the quantity of ox-gall. Rowney's is the best manufactured. As regards colouring tracings, you should always colour on back, as the ink lines are liable to being obliterated on applying the colour. For your walls use lake or carmine; wood, burnt sieuna; slates, prussian blue, or indigo and lake. Mix your colours very dark, so as they may appear of proper strength on opposite side. DRAUGHTSMAN.

[3856.]-SPEED, &c., OF TRICYCLES.-I believe the average rate on tricycles driving by levers is about 7 to 10 miles an hour (and, indeed, this is the aversge rate of most veloeipedes). Some of the inventors assert that they are easier than bicycles, but I do not consider they are so in practice. except it be that the seat is easier. The one spoken of by Andrew Johnson would do well for two riders; but for one a tricycle is a miserable affair unless it drives by levers. cost ought to be about £8 (I can make good ones at that). The driving wheel ought not to be more than 38", and the cranks 6".-S. JAMES.

The

[3861.]— -SIZE OF NOZZLES. -The rule is 3-16ths internally, 5-16ths for water; and for steam it is, and internally .-J. HARDMAN.

[3869.]-WEIGHT OF WATER.-The bucket will apparently increase in weight as it approaches the top, this i owing to the decrease of leverage by the roller becoming thicker with the rope coiling round it; and not to any differenee in the weight of the bucket from difference of distance from the centre of the earth. Mode of calculation. Let a = diameter of roller; b = thickness of roping wound on; 10 weight of water at bottom of the well; and wet weight of water at top of the well. Then as a : (a + b): ; w: wt.-B.

plains of his bucket of water being so much heavier at the [3869]-WEIGHT OF WATER.-"Countryman" combottom of the well than at the top. He wants an explanation of this, and a simple rule to work it out. The real truth of the matter is that his bucket of water is actually of less weight at the bottom of his well of 90ft, than at the top Seeing he has gone so far into the earth, the gravity will be a

trifle less. The increased weight can only be the rope or ehain that he winds up with, and if he knows what a foot of that weighs he can calculate for himself; but as he finds it hard work to wind up the water while the bucket is at the bottom of the well, he should have his roller that he winds up on tapering, and so commence winding at the small end of his roller. He will find this plan a great relief.-H. P. [3882.3-DOUBLE MOTIVE POWER.-Consult a properly qualified engineer and millwright on the subject. These two motive powers cannot overrun one another if properly governed by governors. If there is not one on the wheel, take all the water, and the engine will govern the difference, unless the quantity of steam power required is very little; connect both powers by a clutch coupling or wheel, that the one can work either with or without the other. When the pinion on shaft is made moveable, it should be keyed on swell with sunk key, and when not required taken off swell and hung clear of shaft.-J. H. [3911.] GALVANIC CELL. The cell described by "Hermit" is called a Bunsen's cell. Nitric acid HNO, is poured into the porous cylinder containing the carbon, and dilute sulphuric acid H,SO, into the glass vessel containing the zine, say about 1 part of H,SO,, to 10 of water, HO. This cell is one of the most powerful, and is also pretty constant. There is one objection to it, however, and that is, it gives off red noxious fumes during action. These fumes consist of some of the lower oxides of nitrogen. Where strength and constancy are required it is very useful, but where constancy without strength is required, I say use a Daniells. I use for electrolysis a battery composed of 4 or 6 Bunsen cells, and this battery auswers very well, The following may represent chemically what takes place in a Bunsen cell. Let (N2O5) represent an hydrous nitric acid, which may be written to illustrate the action as (NO¿O)—i.e., the nitrogen tetroxide (NO) and oxygen (O):1. Before chemical action.

C, + N2OO + N204,0 | H2, SO4 + H2SO4 + Zn; 2. After chemical action.

C,N2OON2O + 0 H2+ SO, H2+SO4, Zn. Now the N2O4 does not combine with the carbon (C), but comes off as red fumes. The compound radical (SO4) combines with the zinc and forms sulphate of zinc (ZnSO4), while the sulphuric acid is made more dilute by the formation of OH, water.-J. HARRISON, Bradford.

A. BOUGHEY,

of course the needles must be equal in every way as to
dimensions and weight.-EXCELSIOR.

find an iron tank much the best; also I should advise him to
[3970.]-STEAMING FOOD FOR COWS.-"R. R" wil
do 50bush. at twice (if that is the amount he uses at one feed).
as the utensils for 50bush. would be very clumsy. I have by
find it-will send it next week if I can; meanwhile any
ine a drawing of complete apparatus, but cannot just now
engineer will give "R. R." information on the subject if he
wants it immediately.-AN OXFORDSHIRE FARMER.
[3972.]-IRON STAINS.-Dissolve a little oxalic acid in
water and apply to the stains; after a few minutes rinse in
clean water.-H. E. GODFREY.

[3972.]-IRON STAINS.-J. H. P." may remove iron
stains by dissolving oxalic acid in hot water in the proportion
of a teaspoonful of the crystals to a teacupful of water; the
parts melted with the acid must afterwards be carefully
rinsed through clear hot water. This method is only
suitable for white materials.-SALOPIAN.

[3977.] BRAZILIAN RAILWAYS. "H. Z. Y.''There is not, that I am aware of, auy line of railway in the city of Bahia, the nearest terminus being Jequitia, some 2 Custom House (lower city), Plaza, to the Barra (upper city); miles from the city. There are 2 tramways from Bomfine to total distance about 6 miles. The Bahia and San Francisco ends at a post. The only other railway in the same province Railway, some 69 miles long, commences at a pillar and is the Paraguassú Tramroad from Cachocira, some 45 miles from the city. This line is in course of construction, to be carried out to the Chapada or diamond district, some 65 leagues in the interior.-J. G.

[3987.]-OIL TESTER-Wm. Johns, Messrs. J. Bailey and Co., of Albion Works, Salford, make a good machine. Price complete, £9 10s.-J. G.

[4000.]-SODA WATER.-Render a neutral or alkaline solution acid with acetic acid, then add acetate of potash, and a little spirit of wine; stir for some time. A white precipitate indicates tartaric acid-no precipitate, citric acid.H. E. GODFREY.

[4019.]-SAFETY VALVE.-Had "O. G." known that our kind correspondent, "T. J. O'C." would have given such detailed and explicit examples on the lever safety valve. I have no doubt he would have paused before sending his [3911.] GALVANIC CELL.-I beg to inform "Hermit' query for insertion; but as he appeals to me personally, I that his cell is a Bunsen's; the cylinder is made of very dense will give him the rule 1 use for finding the size, length of charcoal. The liquids used are, dilute sulphuric acid round lever, &c. The orifice through the safety valve is generally the zinc cylinder, and nitric acid round the cbarcoal. The about 8-10ths of a circular in. per horse-power, or a circular system is as energetic as Grove's, but does not last so long.-inch to 14 horse power; or the surface of the boiler exposed to the action of the fire in feet, multipled by 305, and the square root of the product will be the diameter of the valve in inches at the smallest part for 201b. pressure to square inch; but as "O. G.'s" boiler is so small, I fear the proportion would be too small to be practicable, as it may be liable to stick, or the have a great effect on so small a valve; so it would be better lever may be a little tight, or many other things that would for him to keep the safe side, and have it a little larger-say 3-16ths or in. in diameter; the fulcrum or centre of motion about the same distance from the centre of valve as the valve's diameter; lever about 24in. or 3in. long. If "O. G." decides on the lengths and diameter, he only requires a rule to find the weight. Rule:-From the required pressure per weight of lever, multiply the remainder by the distance in square inch in lbs., subtract the weight of valve and effective inches from centre of motion to valve; divide this product by the distance in inches between the centre of motion and the Iweight; the quotient is the weight in lbs. required on the ever.-JONAH.

[3940.]-THREE WHEELED VELOCE. -The best way is to have one hind wheel loose on the axle, and the other one fixed on it, for turning.-S. JAMES. [3943.]-BEES.-S. W." need not be afraid to hive the first swarm he may have in the hive or box of old comb he has, only taking care before hiving the swarm to well sprinkle the layer of comb with sugar and beer, or honey and beer, about pt. To show that bees are not very particular about taking to furnished apartments, I will mention a case which occurred among my own bees about 3 weeks since. One of my stocks died about the middle of February; I ascertained they were quite dead, and that the hive (one of the old straw ones) was full of comb, and then placed it in its former position between the 1st and 3rd hives in the row. About the 15th of May a swarm from No. 3, after manoeuvring about the front of the hives for a short time, quietly took possession of the empty hive. The next morning I found in front of the hive nearly a pint of dead bees and rubbish These industrious little workers had removed in the night. they have gone on well, and I shall immediately put on them a super hive or cell glass. I shall be glad to know if any of my brother bee-keepers have tried the use of chloroform in taking honey from the old straw hives. I have done so, and found it answered very well, only it is a good bit of trouble, which perhaps was on acoount of the primitive implements I used, being just what came to hand. The old method of destroying bees to procure their honey seems very cruel. 1 shall be pleased to hear from some of our more practical and extensive bee-keepers.-AN OXFORDSHIRE FARMER. [3944.]- ARITHMETICAL QUESTION. Every circle may be conceived to be a polygon of an infinite number of sides, and the semi-diameter must be equal to the perperpendicular of such a polygon, and the circumference of the circle equal to the perimeter of the polygon. Describe any polygon on paper, and cut out each side and place them together, and they will form a parallelogram whose length is equal to half the number of sides, and breadth equal to the perpendicular semi-diameter.-J. SHARPE.

[4021.]-COINS.-The first coin of "Veloce" is a common sixpence of Queen Anue of 1711, belonging to her second issue, after the union of England and Scotland. It is not worth more than 1s., unless very fine. The obverse bears the bust of the queen to the left, ANNA DEI GRATIA (Anne, by the grace of God) Reverse: 4 shields of arms arranged in the form of a cross, and each crowned. The star of the Order of the Garter in the centre, and the date, 1711, above. MAG. BRI. FR. ET. HIB. REG. (Queen of Great Britain, France, and Ireland). See my "Guide to English Coins," part ii., p. 119. The second coin is a Hamburg piece of Charles VI., Emperor of Germany from 1711 to 1740.-HENRY W. HENFREY, M.N.S., &c.

The

which he refers is a 4s. piece of Hamburgh; it is base silver; [4021.]-COINS.-In answer to "Veloce," the 2nd coin to the one now lying before me of the same year has a doubleheaded eagle, as I think they all have, and not a griffin, as he supposes. The other I don't know.-J. G. SYMMONDS. [4024.]-GALVANISING CAST IRON-The first thing [8956.]-CHEMICAL.-TO" R. TERSET."-The following immering it in dilute sulphuric acid; after the iron has been in the process is to remove all rust or scale from the iron by s after Frankland's notation. Question 1. A litre of methyl. in the acid for a few minutes plunge it into cold water. SCH gas CHI (molecular weight 30, and density 15), at 20°C. iron being now ready to receive its coating of zinc, put it in a bath containing zinc, which, previous to its being melted, is and 760mm., will be 0896 x 15 x = 1.252grms. covered with a layer of dry sal-ammoniac (hydrochlorate of ammonia); ; this melts also, and forms a viscid coating, which Question 2. Prepare a solution of Nallo by means of CO2 prevents the rapid oxidation to which molten metal is liable. Nao, OH, and Cao. Now mix the CH,I with sufficient The bath is constructed of fire-clay. The iron is simply of the Nallo, and distil over a water bath, when ethylic dipped into the zinc, or made to pass through it, and when alcohol will come over and sodic iodide remain. CHI+pulled out it is effectually coated.-CUTHBERT.

273 273 + 20

NaHo =
CH 31
CH2
3Ho + NaI. This alcohol may now be
mixed with the CrO,Ko, and the SO,Ho2, when it will be
oxidised at the expense of the chromic acids, and acetic acid
formed. The following will express these reactions:-
Cro2Ko2+ SO, Ho2 = SO, Ko2+ Cro2 Ho

=

Cro2 Ho O2 + CrHog (CH3 SCH3 + O2 = (CH.Ho + OH CO Ho NIGHT SCHOOL BOY. [3961.]-CAST IRON FOR TURNING, &c.-In answer to part of Faber's" query about moulding composition, I beg to state that gutta percha, applied with considerable pressure, is far better than wax; and Gore, in "Electro-Deposition," recommends part of marine glue to be added to the gutta percha by melting them together.-Onra. [3966.]-TABLES WITHOUT DECIMALS.-You should at once learn decimals, and know the fractional value of money, weights, measures, or any other material.-J. H.

[3967.]-GALVANOMETER NEEDLES.-It is generally admitted that whether the needle of a galvanometer be highly or feebly magnetised, the deflections will be equal. The earth's attraction for each needle being in the same ratio as that of the coil (made a temporary magnet by the current),

POISONOUS TEA.-The trade in the lowest class
of adulterated tea still continues, and this month Dr.
Muter reports that there have been no less than 80
chests exposed for sale, of which he procured samples.
This so-called tea consisted of a variety of rubbish,
and is being sold for 24d. per lb. It yielded an ash
filings, and under the microscope presented the struc-
amounting to 22-86 per cent., consisting chiefly of iron
tures of many foreign vegetable matters.
worst sample which came under his notice was a green
But the
tea from India, highly faced, and yielding an ash con-
taining a quantity of copper. This is really a sad
thing, because it has previously been a noteworthy
practices, and that tea from our own possessions could
fact that our Indian planters refrained from such
be depended on. We trust, however, that this
case, may discourage the unprincipled persons who
discovery and exposure of what we think is the first
are thus disgracing the commercial honour of our
Indian planters. The colour seemed to have been
produced by roasting in contact with copper, probably
in copper pans.-Food Journal,

prompt

NOTES AND QUERIES.

OUTDOOR SCIENTIFIC PURSUITS. As the time is come for outdoor exercises, ame inents, and scientific pursuits, we should be glad to tions on matters more particularly appertaining to the receive from our numerous correspondents contribs season, including information for scientific tourists, microscopists, geological and botanical inquirers, lovers of natural history, &c. We should also like to ing, moth gathering, and a dozen other cognate subplace on record practical suggestions on boating, fishjects. The seashore, always attractive, now teems with interest to the observing eye and reflective mind. In fact, we should be glad to receive from any quarter any fragment of information which would be read with interest during the summer and autumn seasons.

[4025.]-HORSE POWER.-How can I prove correctly the horse power of an engine?-NOVICE.

[4026.]-BOILER PRESSURE.-From what point in the pressure of steam in the boiler does the high pressure commence?NOVICE.

[4027.]-MEDICAL COIL-Having made a coil according to "Sigma's "directions, would that gentleman, or any brother reader, be so kind as to inform me where I can get the pillars for the electro magnet contact breaker and pillar, with a ring and the pillar to hold the end of the spring and studs, and to allow the spring to pass through one to hold the screw, pivot described by "Sigma," as I have written to five or six different places and cannot get them?-A COAL MINER.

shire, and have a vivid recollection of the floors being smooth [4028.]-FLOORING.-As a boy I lived in Nottinghamand polished like marble. I have since been informed that they are made of unburnt gypsum ground fine and beaten, mixed with a little water, until quite hard. Can any of your readers who reside in the parts of Derbyshire or Nottinghamthe modus operandi, and from whence the best gypsum for shire where gypsum abounds, give me any information as to the purpose can be obtained?-ARCHED FLOOR.

[4029.]-FIXING COLOURS IN COTTON MATERIAL. blue print, also in mauve and green?-Goss. -Can anyone inform me how to fix the colour in a black and

correspondent kindly inform me what is the new process of [4030.]-LEAD INSCRIPTIONS ON STONE.-Can any letting inscriptions, &c., in lead into stone? The lead, I believe, is melted by some chemical process, and run in cold, so as to avoid shrinking. The advantages of this method are so obvious that I shall be greatly obliged if anyone can tell me how it is done?-J. B. FOWLER.

diameter, and 4 threads in inch. I find it too hard to drive. [4031.]-LEATHER CUTTING.-I cut through the soles of boots with a steel die and a screw press, screw 2in in I should like to know the strength of a long lever with pinion working into a toothed rack, the rack to press through the die. Can any of your correspondents inform me if this is better than the screw press?-J. C.

form me what sized lathe his grip chuck, described on Oct. [4082]-GRIP CHUCK.-Would "J. K. P." kindly in22 last, was made for. Is the length (4in) too much for a 4in.

centre lathe ?-J. D. L.

[4033.]-SLIDE REST.-Would "W. H. N." the author of the working drawings for slide rest in your number of the 3rd inst., kindly describe the method of constructing the tangent wheel of a spherical slide rest?-J. D. L.

[4034.]-BOAT STEERING.-I have a 25ft. whaleboat, and find the rudder-head for yoke-lines gives too little power when under sail in a stiff breeze. The distance between the lines is 14in., the thickness of rudder lin. Can any fellowof steerage by making the distance between the yokelines reader tell me in what proportion I shall increase the power 24in., assuming part of rudder under water to be 15in. by 14in. ?-EXCELSIOR.

keys of which at the right hand sink down, thereby losing
[4085.]-ORGANS.-I am acquainted with an organ, the
their leverage more or less; the pipes do not speak when they
are thus down; the sinking occurs at this season of the year,
and the keys right themselves at the approach of winter.
Could any brother subscriber tell me the reason, and suggest
a remedy? The organ has been built about 12 years.-J. N.
[4036.] BOTANICAL CHEMICAL.-Chemicals are
applied to the roots of a plant, ad effect a change in the
colour of its bloom. Now, are se: lings raised from a plant
so changed likely to retain the colour so acquired, or to go
back to their natural colour? I am inelined to think the
latter, and should be glad of the opinion of some of our
botanical readers?-S. ROGERS.

[4037.)-RULE FOR FINDING SIZES OF WHEELS. -Will J. K P.", or some other reader let me know how the relative sizes of wheels are found; for instance, I have a wheel Sin. diameter, with 120 teeth, what size ought one to be to gear with it with 30 teeth? What is the rule used by practical men for the purpose?-R. T.

[4038.]-CONDENSER FOR MEDICAL COIL.-Will "Sigma" say whether a condenser would add to the power of the medical coil described by him, and if so, how would he connect it?-R. T. [4039.]-BAROMETER TUBES.-Wiil any reader inform me how to fill my barometer tubes, so as to avoid the air getting in? I have tried, but failed-STULTUS. wheels, the larger of which runs loose on the shaft, and is [4040.]—WHEEL GEARING.-I have a pair of bevel connected by a clutch. I wish occasionally to vary the speed, and could do it at these wheels by slipping a collar and the bevel wheel back, and putting a larger pinion on. having the same bevel at the pitch line, would not run well have, however, been informed that a larger pinion, though Will some of your correspondents give an opinion, especially anyone who has tried it, and oblige.-KIRKBY.

[4041]-BICYCLE QUERIES.-How can I alter a benzolene lantern so as to make it suitable for a bicycle? I have taken the sponge out and tried to burn colza oil; but the light dies out after riding for a few minutes. Is oil or candle used for these lamps? What part of the foot is the best to drive the bicycle from for speed and ease?-LERK.

me know what size wire would be the most suitable fo- a [4042]-MAGNET-Will some brother reader kindly let horseshoe magnet 3in. long, and composed of iron Jin. diam.;

smith subscribers or any other thoroughly acquainted with very cheaply by Water Company's water, it would be prefera- inform me as to any really good book upon harmonium or

ERRATUM-In Reply 3723, "Glaze for Pottery," on page 236, the formula for glaze for pottery should read "100 parts white lead, 20 parts flint, 40 parts stone, and 5 whiting." "I NOTE with others your great improvement and useful- E. SLATER, with another letter on cotton spinning. ness.-W. N. LAIDLER, 9, Edward-street, Paul's-road, Bow-G. J. WALKER expresses a hope that "F.R.A.S" may have common, E.

"How is it possible you can issue such a well printed BBRIRO.-First query inserted; for information sought in the furniture springs for seats and mattresses.-A communica

"I REALLY believe the ENGLISH MECHANIC is doing more to promote genuine technical education, and to spread a knowledge of the useful sciences amongst all classes, than all our art and science schools, which are sustained at a considerable cost, put together."-W. H. T., Manchester.

J. S. ASHTON.-Consult indexes. The numbers inquired for Gernon, Essex, improvements in machinery for engraving or

A. T.-We know of no such book. Perhaps you mean
Brewer, not Ure.

D. WRIGHT.-Such a proposition might appear invidious.
HY. JAMES.-We don't know the address.
URBAN.-Thanks for expression of good opinion. As a rule,
yon are right about the exclusion of medical queries.
W. H. HENFREY.-" Ancient Coins " next week.
PAUL GILL.-We simply thought you merely glanced at the
question you wrote on. You say "I am fully persuaded that
it is your earnest wish to treat your correspondents im-
partially, but almost unconsciously we now and then re-
pudiate things only because they cut against the grain or
fame of our good friends." All are our good friends"
who have useful information or criticism to offer. As we
cannot insert all the letters we receive, we are obliged to
make a selection, and as a rule the most substantial or the
most suggestive have the preference. Of course we may
be mistaken, but we endeavour to act for the best, and
never to forget the interests and tastes of the mass of our
readers. Let "Paul Gill," who is unquestionally an
educated and intelligent man, send us a letter on any sub-
ject in harmony with our general purpose and tendency,
and not likely to evoke a personal controversy, and the
letter shall be inserted. He will then be numbered
with "our good friends," because he adds to the common
stock of knowledge for the common good.
URBAN.-We intend to give reports of scientific societies after
we have amalgamated Scientific Opinion.
"Outdoor Seientific
W. T.-See our notice elsewhere on

"I BEG to add my testimony to the very able manner in which our MECHANIC is conducted. Although constantly interested in machinery of great diversity, and therefore a sub-J. scriber to several of our principal mechanical journals, I freely admit that I can find more really useful reading in our twopenny journals than in all the others put together.-ISAAC $1 WHITESMITH, Covan-street Foundry, Glasgow.

APPLICATIONS FOR LETTERS PATENT DURING TUE
WEEK BNDING JUNE 6, 1870.

158: P. D. Hedderwick, Glasgow, improvements in printing
1583 A. Dyson, Huddersfield, improvements in machinery or
apparatus for carding wool

1583 L. Gardner, Manchester, and T. Bushby, improvements in pill making machines

1584 B. Hunt, 1, serle-street, Lincoln's-inn, electro-magnetic apparatus for moving panoramas, or other things required to be exhibited.-A communication