Abbildungen der Seite
PDF
EPUB

decrease of attraction between the earth and moon?

§ V.-POROSITY-DENSITY. Porosity is the existence of some space between the particles of matter. A sponge is an excellent There is little more to be said of this example. property than that all bodies have it, varying in degree. Gold, the most compact, steel, &c., have pores. There is no solid the matter of which cannot be forced into a smaller space. There must have been room for the particles to move into.

Density is a very important property. By the name is signified the quantity of matter in a given space. It differs, therefore, essentially from "weight," which does not take the bulk, the size, the volume into account, or when these terms are used, it is only meant to convey the idea of a certain amount of matter without any comparison of volume. To make the notion of density clear, take an example. Let A and B, Fig. 34, represent two cubes of equal capacity. A is filled with water, B with mercury. Now mercury, in round numbers, is thirteen times more dense than water

i.e., that in the same volume there is thirteen times more matter in the mercury than in the water. Weight has no reference to volume. It says, "There are 2, 3, 4lb. of mercury." Density, on the contrary, is the weight of a given volume. It says, "in that volume there are 2, 3, 4lb. of mercury."

Weight refers to some understood quantity of matter-an ounce, a pound, &c., taken as a standard, no matter what the body be; an exact. ounce of wood will do as well as an ounce of brass.

Density refers to no fixed quantity, but to some determined body as the standard of comparison, no matter what the volume, provided equal volumes be taken of the standard and body to be compared. The relative weight of these equal volumes gives the density. Of this density much in chemistry, just now enough to understand what it is, and to see briefly its chief laws. The definition of density is contained in the M quantity of matter, V volume

M

formula D= V

containing it.

No. 1. Laws. These are important, yet simple, and easily remembered.

Law 1. All bodies have density. liquids, gases, have their own density.

Solids,

Law 2. The density increases with the quantity of matter in the same volume. As there is more matter within the same bulk the body is more and more dense.

Law 3. The density decreasss with the increase of volume, for the same quantity of matter. The greater the volume, the quantity not changing, the less is the density of the body.

Law 4. When the densities of two bodies are equal, the masses are directly proportional to the volumes.

Law 5. The masses being equal, the densities are inversely proportional to their volume. Law 6. The volumes being equal, the densities are proportional to the masses.

No. 2 Proofs. These are a remarkable evidence to the student of the utility of even simple formula. The laws may be all remembered by means M of the formula D, which contains all e V laws.

Law I. Every body has a certain quantity of matter, and occupies some space. Therefore D has always some value. In the gases the volume is evident, and that they have M is proved by their

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

b't of wood: not so those of a bit of glass. This property depends somewhat upon density; it exists only in solids, and in these it is relative; hardness in timber would be called softness in stone, iron. There is no body absolutely hard, at least, as yet, none discovered which can not be deprived of some matter.

Brittleness.-Easily divided by a shock. Belongs to solids only.

Malleability. Easily changing form or volume, without injury to texture, by compression cr percussion. The name is taken from the hammer. (Latin, malleus.) An important property pos sessed by some bodies, especially amongst the metals-lead, tin, gold, platinum, &c. The wellknown gold leaf is a familiar example. Its very thin sheets have a thickness not greater than of an inch. Recently iron has been

1

200000 of paper, and employed for writing a letter upon. laminated," as the term used is, to the thickness Ductibility.-Easily changing form or volume by being drawn through openings finer and finer. (The name from the Latin, duco, I lead.) This property it is which permits the making of metallic wires. Only some amongst the metals possess ductility, and it is a remarkable fact that some malleable metals are not ductile, and vice Wire drawing, as the process is called, is effected by drawing metals through conical-shaped holes is a plate of steel. Each hole, Fig. 35, is a little smaller than the hol which preceded. The wire is drawn through one hole after another, until the required diameter is reached, Fig. 36. Some metals, not ductile, are made into wires by being forced through holes-for instance, the new metals, magnesium and thallium. Ductility would seem to depend, at least in part, on the next property.

versa.

Tenacity. The power of resisting an effort of drawing asunder the particles of a body. Attraction of cohesion, the cause of this property's varying so much, tenacity must differ much in various bodies, and shows but little beyond the solid state. It does not seem to have any dependence on

1

dersity; steel wire -in. will bear 134lb.

100

Platinum, same di meter only 161b., although platinum is almost three times as dense as steel. (To be continued.)

MESSRS. CUNNINGHAM AND MCCARTHY'S IMPROVEMENTS IN OBTAINING MOTIVE POWER.

HIS invention, patented by W. J. CunningTham, or 100, Few Oxford-strect, and Alfred Patrick McCarthy, of Bloomsbury, consists in the application of springs of any description or any equivalent power so combined with wheels, levers, and other apparatus as to act alternately or simultaneously the one on the other, and by this means aid or cause the propulsion of any wheeled vehicle. Fig. 1 is a longitudinal section of the apparatus, Fig. 2 combining sections through A B and C D, Fig. 1. The said springs are contained in boxes or cases a al, free to revolve on a shaft b, and have attached to them gear wheels c d in gear with pinions ef on the shafts gh of the winding-up wheels ij, which are alternately placed in and out of contact with the ground. On the same shaft b as the spring boxes is a gear wheel & taking into a pinion on the driving shaft m of the machine, on which are the two carrying wheels n, so that the action of the springs being communicated to the shaft b causes the gear wheel & to revolve, thereby imparting its

liquids and action (mechanical) on solids and AS before, of these in groups or singly, accord-motion through the pinion 7 to the carrying wheels,

Laws II., III. Looking at the formula it is clear that as M grows larger, V remaining the same, the quotient of the division most increase, therefore the density. Again, while M remains the same, if V increase, the quotient must decrease. Law IV. Comparing the densities of two

[merged small][merged small][merged small][merged small][merged small][merged small][subsumed][merged small][ocr errors]

M'

V'

(1).

For the densities

being equal, the expressions of these densities must be equal.

ing to importance.

§ I-COMPRESSIBILITY, DILATABILITY, HARDNESS, &c.

Compressibility, is the permitting reduction into a smaller volume. Some bodies have this property very evident; examples well known; others have but little sign of it-thus iron, stone, water. It exists in all, in a greater or less degree, and is the cause of the apparent penetrability observed in bodies.

and thus propelling the machine. But so that the action of the springs shall be continuous they are alternately acted upon and kept up to their working power by the wheels ij in the following manner :-On the spring shaft bare small fast and loose pulleys o p, from which a band or strap passes to a corresponding pulley q on an auxiliary shaft r, on which is a conical pulley s corresponding to another conical pulley t placed in the reverse direction on the shaft u, and a strap connects these said conical pulleys & and t, so that Dilatability is the power of occupying a greater by shifting the said strap from right to left, or volume. It is the reverse of compressibility, and, vice versa, a slower or faster action may be imlike it, very evident in some bodies; not almost parted to the cams v w, on the shaft u. perceived in others. The gaseous state is the great said cams act upon the upper ends of sliding example. blocks y, carrying the bearings z b1, of the Hardness.-Better understood than expressed. It is the power of resisting disintegration-divi-winding up wheels, and alternately depress

sion.

A knife separates easily the particles of a

These

the said wheels, which by their contact with the ground during the progress of the machine as

[merged small][merged small][graphic][graphic][ocr errors][subsumed][subsumed][subsumed][ocr errors]

and will form a valuable addition to steam engines
by enabling a comparatively small power to per-
form the same amount of work as a greater power.

ASTRONOMICAL SOCIETY.

W. LASSEL, ESQ, F.R.S., PRESIDENT, IN THE CHAIR. THE President expressed the deep grief that the Society experienced on hearing of the death of the late able President, Admiral R. H. Manners, and remarked on his many amiable qualities, and the interest he took in promoting astronomical science.

Professor Selwyn exhibited to the Society a chart that he had received from Sir John Herschel, in which were roughly mapped all the solar spots observed by Mr. Carrington. Sir John stated that his object was to discover whether any particular region of the sun showed any decided tendency to macularity. Had he been successful in detecting any locality where spots appeared more frequently on the solar dise the chart would have been made more accurately, but not having been successful, the chart was submitted to the attention of

the Society in its rough state.

poses. The particular wants of spectroscopy require five stand a little of the nature of spectrum analysis. For the skilled observers, to be assisted by three others, who underobservations with the polariscope it seems impossible to dispense with fewer than three skilful observers, who would require, probably, three assistants. The number of skilled observers is, therefore eleven, and with their assistants and

persons required for each station. About sixty gentlemen have expressed a wish to take part in this expedition, so that two stations can be completely furnished, one at Cadiz, and the other at Gibraltar. It is necessary that the directors of the expedition should know what observation each volunteer is competent to make, and whether he is willing that his services shall be transferred to any other department that necessity may render desirable. Mr. Airy concluded by expressing his opinion that the observers who had taken the observations with the polariscope in former eclipses knew nothing of the use of that instrument, and that it was indispensable that every observer should satisfy some competent person that he knew what polarisation is, what the plane of polarisation is, and what the plane of polarisation is when he sees it.

Mr. De la Rue said that he believed an expedition had never been organised which was so likely to have a successful issue as the one under discussion. Gentlemen the most competent to bring about a success had expressed their intention of taking part in the expedition, there was required only a master mind to direct the proceedings, which he hoped would be found in the person of the the Astronomer Royal. Several observers presented their observations of the occul-invitation of Mr. De la Rue, and left the matter doubtful; The Astromoner Royal could not undertake to reply to the tation of Saturn, on April 19th, with their remarks upon the at a subsequent period of the evening Mr. Airy said that, phenomenon. Three distinct observations had been made at the considering all the contingencies and requirements of the Royal Observatory; Mr. Jovnson, Captain Noble, and Mr. observers, it would be desirable that the steamer should be Talmage, had also observed the occultation. Mr. Talmage also observed the occultation of Titan, and remarked that and he ready to start on Saturday, the 3rd of December; and that, taken the trouble to compute the place of some of the brighter totally unexpected, it might be desirable to detach a party to in case the number of volunteers increased, in a manner satellites, he might equally well have observed their occultathe East Coast of Sicily, which would require the expedition tion also. to start still earlier.

caused to revolve, thereby rotating the pinions ef, from which motion is communicated to the gear wheels c d, attached to the spring boxes a al, and thus wind up the springs in advance of the speed of rotation of the gear wheel k, thus ensuring their constant action. The said sliding NOTES FROM THE PROCEEDINGS OF THE ROYAL other general observers, would make a total of twenty-six blocks y, act alternately upon the ends of a lever oscillating on a fulcrum di suspended from the cross frame el carrying the bearings of the cam shaft, by which means the cams have little or no work to do in rising the wheels, as they exactly balance one another, thus preventing a great strain being thrown on the working mechanism of the machine. If a greater amount of adhesion is required on the winding wheels, the cross frame el may be lowered by the screw fi worked by the hand wheel g1. and having its bearing in the cross bar h1. The bosses on the winding shafts g h at all times bear against a guide it, and are connected to the shaft b by radial arms j1, thus ensuring the wheels ce and df being always in gear with one another. One or more guide wheels 1 is or are adapted to the fore end of the machine, and actuated by a hand wheel, by which means the course of the vehicle to which this apparatus is applied is directed. When the machine is going forwards the pawls m acting on the gear wheels c d, attached to the spring boxes sre placed in contact therewith to prevent their springing back in a contrary direction when not acted upon by the Mr. Penrose submitted to the attention of the Society, winding wheels, and when the machine is resome observations of occultations, solar spots, and of the quired to go backwards the e pawls m are lifted variable Algol: concerning the latter, Mr. Penrose stated out of gear with the wheels c d, the pawl n hav- that the period required some slight correction, as the observed time of the minimum brightness was three hours in advance ing been previously thrown into gear with the of the computed time. The observations of solar spots (a wheel to prevent its forward driving action. diagram of which was presented to the Society) did not apIt is evident that the action of the spring boxes pear to indicate that cuplike depression which these plienoand spring shaft may be reversed so that the mena usually present. Mr. Browning remarked that in his observations of solar spots the same peculiarity had often premachine may be driven either by one or the other.sented itself when the penumbra had appeared nearer the When it is desired to stop the vehicle all the centre of the sun than the limb. pawls are placed in gear, by which means the whole power of the springs is store up for a new start, and the course of the machine gradually arrested. The springs may be additionally wound up by hand if required, and the self-acting winding wheels may be placed in and out of contact with the ground by hand instead of by the means described, and several springs may be placed on one shaft so as to have a continuous action, by which arrangement much power will be gained. The carrying wheels may have clutches applied to their axles, so that they may be disconnected therefrom when turning, or at other convenient periods, and the two or more springs may be arranged to act simultaneously if desired.

A whistle acted upon by compressed air or otherwise may be placed on any convenient part of the machine so as to signal its approach in the same manner as obtains a present with steam whistles and the pawls may be made to act upon spring balances to indicate the amount of power given off by each spring.

This machine or apparatus may be employed either for railways, road vehicles, stationary engines, clocks, or any other purpose for which motive power of any description is required, and

Mr Lockyer said that he believed that during the last year a great change had taken place in the appearance of sun spots, and submitted as a working hypothesis that possibly the photospliere at the time of maximum macularity was thinner than at the time of the least frequent appearance of

spots.

Lieutenant Brown offered some meteorological observations

Government.

made at Gibraltar from 1860-9, towards the end of December
in each year, with a view of determining the probability of
of these observations was to show that the sky at that period
the Solar Eclipse of 1870 being visible. The general tenor
of the year was generally free from cloud, and that the
chances were greatly in favour of complete observation.
The President remarked that a great number of letters had
in the expected forthcoming expedition, and that in the course
been received from gentlemen volunteering their assistance
of a week, the Council of the Society would meet to discuss
the most likely method of procuring the co-operation of the
Mr. Airy repeated the remarks that he had made at the pre-
vious meeting of the Society. From the experience gained
by English and American observers in former eclipses, it ap-
peared that the three great subjects of observation which
required especial attention and especial training were photo-
graphy, spectroscopy, and polarisatlon, and this division was
so necessary that he had no fear
of its being disputed.
The number of persons who will be required at one station
to carry on the observations by photography with good effect,
is three well-skilled observers, thoroughly versed in the use
of photographic apparatus, and able to adapt themselves to
the singular circumstances of the phenomenon. These three
observers will require two assistants, who need not be so
well acquainted with photography, one of whom, if possible,
should be a carpenter, who may be valuable for other pur-

Prof. Grant hoped that a certain number of artists and draughtsmen might accompany the astronomers, as their services would probably be very useful. It was announced by the committee that the names of several had been re

ceived.

Mr. W. T. Lynn communicated a paper on the "Proper Motion of the Star Groombridge, 1830," derived from a discussion of the Greenwich observations for 20 years, and which tended to establish the hitherto received value of its

proper motion.

Mr. Proctor addressed the Society on the subject of the resolvability of star clusters being regarded as a proof of distance, and in the course of the discussion which followed, Mr. Stone expressed his opinion on the cause of the increased proportion of small stars that become visible as the aperture of the instrument is increased. For the purpose of explanation, Mr. Stone considered the stars as being collected in concentric rings around the solar system, at increasing distances, and supposed stars of all magnitudes equally distributed in these rings. Taen the stars of the first magnitude in the first ring are our first magnitude stars. only the stars of the second magnitude in the first ring, but The second magnitude stars may be supposed to embrace not the stars of the first magnitude in the second ring. For third magnitude stars the first of the third ring will be excluded, and so on down to the eleventh or twelfth, or any magni

tude.

and described an ancient astronomical instrument of the 17th Mr. Williams, Assistant Secretary of the Society, exhibited century, the work of Campini, and late the property of Dr. Lee. The diameter of the object glass was about 2in., but the diameter of the eyepiece, which consisted of three lenses, was about 5in. The field of view was said to be very flat, and the definition good, though the tube being made of vellum, the flexure of the instrument interfered considerably with its performance. The focal length was about 9ft., and the weight about 21lb.

THE ELECTRIC FULGURATOR.

AT the recent annual conversazione of the Plymouth Instituton and Devon and Cornwall Natural History Society, held a Plymouth, Mr. J. N. Hearder, F.C.S., exhibited a new and extraordinary apparatus, to which he has given the name of

Electric Fulgurator, having for its objects the production of electric sparks or discharges of statical or frictional electricity of immense length precisely resembling lightning flashes. The effect is produced by a peculiar arrangement of large Leyden jars, which are all insulated on separate glass pillars, Sft. high, fixed in a frame and connected by levers, which permit them to be joined together, either as an ordinary battery, or turned into a position which connects the inner coating of each with the outer coating of the next. The jars are first charged as an electric battery from a powerful glass electrical machine, and when sufficiently charged are suddenly dissevered from battery connection with each other, and are thrown into the intensity, or, as it is sometimes called, cascade position. The discharge takes place between the balls of a suitable discharger connected with each terminal. By this arrangement prodigious sparks of great length are obtained, resembling zig-zag flashes of lightning, accompanied by a loud report. The apparatus, consisting of thirteen Leyden jars, gave sparks in free air of 3ft. 6in. in length, very thick and crooked, and of a brilliant bluish-white colour. The deflagrating power of the apparatus, as exhibited in the combustion of metal leaves and wires, appears to be greater in the intensity than in the quantity arrangement. When this discharge is made to pass through heated air its length is amazingly increased. Sixty-three small spirit lamps, each having two wicks, were arranged in a long ebonite trough, so as to form a line of 126 spirit flames, extending to the length of 9ft. Over these flames a brilliant spark passed with such facility from a moderate charge that Mr. Hearder calculated that a full charge would be able to pass more than double the distance. When the charge was a little reduced the sparks still passed through the flames in a less brilliant form, but producing a bright spot immediately over the top of each wick, giving to the whole the appearance of a long string of brilliant beads. Mr. Hearder stated that, although this apparatus originated with him, it was not now as regards date, for he had shown the society a similar arrangement, though on a very much smaller scale, more than 40 years ago. Its present more imposing form was entirely due to the zeal and liberality of the gentleman before mentioned, who, being desirous of ascertaining to what extent the principle admitted of development, had given him an order to construct the apparatus now before the society. The conclusions arrived at were, that with suitable apparatus and accommodation, and electrical machines of adequate power, the arrangement might be almost indefinitely extended, and that sparks of 15 or 20ft. in length in free air would be by no means difficult of attainment. The present apparatus originally consisted of 15 jars, which gave sparks of 5ft. in free air. In conclusion, Mr. Hearder remarked that this apparatus opened a new field for electrical investigation in connection with the effects of quantity and intensity in relation to statical electricity, a subject never yet attempted for want of suitable apparatus, and he was bound to say that the results of the few experiments he had been able to make are such as could hardly have been predicated with our present notions of the action of the Leyden jar.

SOLAR ECLIPSES.

THROUGH the kindness of Prof. Henry Morton we are enabled to give a brief account of a lecture on the above subject given by him for the benefit of the Franklin Institute. We have before had occasion to refer to the popularity of this eminent lecturer, as well as to the enormous scale on which he conducts the most successful experiments; and the lecture on solar eclipses, which was demanded a second time, illustrated as it was with the most brilliant experiments, fully sustains the high reputation he has gained both in the old and new world. After describing experimentally the causes of an eclipse, the umbra and penumbra, the law of direction, the total eclipse, and the prominences, the lecturer proceeded to illustrate the formation of solar prominences, by means of a tank and a coil of wire (see woodcut).

LETTERS TO THE EDITOR.

[We do not hold ourselves responsible for the opinions of our correspondents. The EDITOR respectfully requests that all communications should be drawn up as briefly as possible.]

All communications should be addressed to the EDITOR of the ENGLISH MECHANIC, 31, Tavistockstreet, Covent Garden, W.C.

All eheques and Post Office Orders to be made pay. able to J. PASSMORE EDWARDS.

I would have every one write what he knows, and as much as he knows, but no more; and that not in this only, but in all other subjects: For such a person may have some particular knowledge and experience of the nature of such a person or such a fountain, that, as to other things, knows no more than what everybody does, and yet to keep a clutter with this little pittance of his, will undertake to write the whole body of physicks: a vice from whence great inconveniences derive their original. -Montaigne's Essays.

DYNAMICS.

THE FUEL OF THE SUN MR. BEARDSLEY'S SIR, "F.R.A.S.," p. 203, has replied so fully to the "Harmonious Blacksmith's" request for an opinion as should not feel any call to give a reply myself, except to Mr. Williams's book" The Fuel of the Sun," that I for a remark or two of "F.R.A.S.""

in the well-known jeu de mot, "what's new is not true, I know more of the book itself, and should sum it up and what's true is not new." fancy he is giving out a new and defined theory when The author appears to he is simply muddling up ideas common to most men the means of thought. It is pretty generally believed who have thought on the subject seriously, and with now that all space contains matter in various forms, as ether, aerolites, and cosmical dust; microscopic planets, in fact. The heat of the sun is commonly attributed to the impact of such bodies continually drawn in. this, the same force of impact which results in heat by What then becomes of the " exhausted Fuel?" Simply the arrest of motion, destroys the bonds which hold the substance together, it is resolved into its elements, and those elements into their ultimate state of division; to use a common illustration, the body is resolved into vapour just as would a drop of water falling on molten iron; this vapour or gas necessarily recedes from the sun by ordinary laws (not by any supposed repulsion), and forms the chromosphere and the absorbing atmos phere, and probably, for here we pass into conjecture, the ether, which carries away into space again both the heat and light produced by the concussion, and also the matter, which, again condensing in distant space after parting with the heat it carried away latent, is prepared again to commence its journey back to the sun, again to repeat that process.

Nature,in fact,exists on a system of perpetual motion, because there is no loss or friction outside of her workings as in our machines; she never loses her force, but its changes of form and operation are what we know

as her works.

Mr. Beardsley has occupied two columns of small print, p. 209, in spreading an intellectual mist which three lines will dissipate. All his argument about the gyroscope and pendulum, which may seem "tall talk" to people as ignorant as himself, is based simply on that ignorance. Now let us at once admit that ignorance on a matter of science is no crime. A man may fairly be in error, and base a false argument on an erroneous observation; every scientific man does so at times, and needs not punishment, but correctior. But when a man challenges the whole scientific world, and calls them idiots, on no better ground than his own very limited perception, the case is very different; such men are public pests, and deserve punishment, for correction they cannot receive.

Is it possible, after all this talk, to open the eyes of this man to the simple fact that the whole of the machinery he is arguing about is in motion, not only the Supporting points, which are solidly connected to the earth; that consequently his argument on the effect that the motion of the earth ought to have on the ball of the pendulum is simple nonsense, because the only effect would be due to the difference in length of the (wo arcs described by the ball and its point of suspension, proportioned to the distances of each from the centre of the earth. Exactly the same argument applies to his former difficulties about the minds. The water and the air are as much attached to the earth as the soil itself, and revolve with it. If the earth suddenly stopped, then the results he supposes would come into The tank is filled with water, and then a solution of cochins any one may see. At first the vessel revolves around effect. It is just so with a vessel of water set spinning, neal is run in on the bottom with a pipette. A single flask the water, which remains at rest; gradually the friction cell excited with bichromate of potash and sulphuric acid is of the sides sets the water revolving, and after awhile, enough to determine the ascending currant, which carries up the whole turns just as though the water were solid and the crimson solution in a very beautiful manner. By inter- fixed to the vessel; stop the motion, and the water rupting the circuit, the red prominence can be made to goes on revolving till its motion is exhausted by settle back, or topple over, so as to assume many of the friction. forms actually observed. To erect the image on the screen Professor Morton used one of Zentmayer's erecting prisms Mr. J. N. Lockyer's drawings of solar prominences, pictures of the corona, and its coruscation, illustrated by a new piece of apparatus for the lantern, and producing on an immense scale the beautiful effects shown by the chameleon top, were very clearly shown.-Chemical News.

Of course if Mr. Beardsley merely wishes to cause mental confusion, and act as a sort of advertiser to that pretender Parallax, he is wise to do his fighting among hedges and ditches, that is, to argue about pendulums and gyroscopes, subjects so obscure to most minds that his assertions as to what they must teach may seem reasonable: but I have asked him to deal with two simple facts in every day experience; he says, chart. Jnst so; will he have the goodness to tell us p. 209, that the sailor can travel anywhere if he has a where a chart is to be found which is not based on the spherical form of the earth? I have seen a great many charts, but none except on this principle. A map of the world on Mr. Beardsley's plan would be so interesting, and such a novelty, that if he can by any possibility devise one, I will ask you, Mr. Editor, as a personal favour, to give him a whole page for its production.

THE INFLUENCE OF THE SUN UPON GLASS. -M. Bontemps, managing director of the famous glass works at Choisey-le-Roi, states that the best and whitest glass made at St. Gobaix turns to a distinct yellow after three months' exposure to the sun. Extra white glass (peculiarly manufactured) has become even more yellow, and gradually assumes a colour known as pelure d' oignon; glass containing five per cent. of litharge wan also affected, though far less perceptibly; crystal glass, made with carbonate of potassa, litharge, and silica was not at all affected (the other varieties referred to contain carbonate of soda); English plate- SIR.--I am afraid that it is out of my power to give glass, from the British Plate Glass Company, of a dis- our friend "The Harmonious Blacksmith," the infortinctly azure blue tinge, also remained unaffected.mation he asks me for. In fact, I am no believer in

CLAIRVOYANCE.

SIGMA.

clairvoyance, by which I do not mean that I am a disbeliever or absolute denier of the existence of such a faculty, but that I do not accept it, simply because no evidence beyond report has ever presented itself to me, though often sought for. My present opinion is that clairvoyance is a misconception of transfer of thought, and that when a clairvoyant gives true information it is because the questioner has the reply in his own mind. Two out of many cases will illustrate what I mean. My watch was once stolen from my room, so I went to a mesmeric friend who boasted the possession of a perfect clairvoyant. She described to me the thief and the circumstances, the going away with it, and pawning of it at a place she did not name, but described as though she saw it, and read the name from over the shop window. She was correct as to the thief: all the rest was pure imagination, the fact being that I had a very strong suspicion as to the first; all the rest I traced out in vain, though I found the place she named. But some time after I caught the thief and recovered my watch, and learnt all the real facts; yet the description was so vivid, that one could but believe facts were being seen by the clairvoyant as they passed before her eyes.

Another clairvoyant being tendered me as evidence, and as having the power of describing distant occurrences, I tested her by going to my brother's house, and requesting him to make some alteration in the

ornaments, and to write me a note saying what was done. The young lady was next day duly thrown into a trance, when she described my brother's house and sitting-room, and told me how he and his wife were another brother was at that moment in their company, engaged, but, singularly enough, omitted to say that I not knowing he was in London. She decribed the altered ornament, which she said was either a large room, pictures, &c., very clearly, till she came to the evidently because I was myself uncertain what was figure or vase, but she could not clearly say which, there; the evening before it was a large alabaster tion; but just as my friend asked me if I were now vase. However, I admitted the truth of the descripnote, unopened till then, and found these words, "The satisfied as to clairvoyance, I took out my brother's vase is removed, and the parrot cage put in its place." This may have been caused by my own doubting faith, I have repeatedly tried to act upon my most sensitive subjects from a distance, but never succeeded. however, because, on the other hand, I readily transfer the impression of my will to them from some distance, providing I have first entranced them, as in the case I referred to a while ago. When, to satisfy a very incredulous person, I left my patient in the house, and allowed him to take me where he pleased, leaving directions to open the door after a certain time, there gone, and yet the observers declared that she did not was no possibility of anyone knowing where we were hesitate an instant, but made as nearly as possible a straight line from where we stood, following the line of street when forced to, and turning corners at the shortest angles, till she came to us, her eyes closed, and in deep trance, and, standing before me, said, "You called me." I therefore recognise the possibility of mental actions at a distance, but never allowing myself to be led beyond what there is good evidence for, I cannot at present admit that clairvoyance is anything but a misconception, due to want of understanding the relations between two minds, and to the excitement of mind caused by the extraordinary things really witnessed by observers, and unconsciously exaggerated in the recitals.

INDUCTION COIL.

SIGMA.

GALVANIC BATTERIES. SIR, Mr. Cunningham, p. 207, is not correct in supposing that the current will escape as readily from adjoining coils as from successive layers. It is a question of relative tension, which may be compared to hydraulic pressure, and the tension increases as the number of coila or length of wire accumulates at the two ends. Now the length of wire in each turns a mere nothing; the difference of tension is nothing s and there is no more tendency for electricity to escape than there would be for water to run from one barrel to another through a connecting pipe if the level were the same in both; but the layers resemble the same barrels raised one above the other, with a tendency to escape proportioned to the height. It is only in very powerful coils that there is any need for interposing anything except the covering and varnish. Even the partitions between the layers would be needless if we could begin the coil at one end, and, working inwards and outwards, instead of longitudinally, complete the whole at the other end. This is not easily done, but is approached to by dividing the secondary into several vertical sections, each complete in itself, and connected to the next. This is the process which Mr. Tucker, p. 212, refers to as tried by another correspondent, and the importance of which he does not seem to sufficiently appreciate.

relieved of his difficulty by reading the paper on the One in a Fog Still" (3802), p. 215, will, I hope, be Daniell's cell, which (p. 159) deals with that subject, though I fear readers will get a little troubled by the displacement of the drawings, as Fig. 37 belongs where 39 is placed, and this latter belongs to a part of the paper not yet printed.

principles which I am endeavouring to make plain in If W. Barber (3818) carefully studies the theoretical my papers on electricity, he will see that the form of cell I described cannot possibly be equal to a bichromate or Bunsen's of the same size, or work an induction coil. It is a common mistake to regard a galvanic battery in the abstract, and compare various forms works they are adapted for. together, omitting from consideration the various

A Bunsen's will work do electrotyping far more cheaply and conveniently an induction coil far better than mine. Mine would than a Bunsen. reduced to a minimum; it is therefore adapted to work In mine, the internal resistance is giving little resistance; but this resolves itself into a question of cost, as we can get the same force from any form by increasing the number of cells in series, This point will be examined shortly, only let readers try to follow out the reasons of things, not merely seek "practical" directions. These last fit only one case, and tend to narrow the mind. causes elevates the mind, and enables us to adapt our A clear conception of plans to all circumstances. SIGMA.

EMPLOYMENT AND ADVERTISING.

SIR, Your readers who want to exchange or sell have an advantage which I beg to suggest might be conferred on those who seek emplopment. To see by the side of "The Sixpenny Sale Column" a Sixpenny Employment Column, would be pleasing to the multitude of English mechanics, and others.

Some of us who know what it is to walk about for a job and receive the disheartening No! in a manner that adds insult to misfortune would be glad to pay 6d. for the chance of a job that we could not call for, including all parts of the country. Apprentices who want to improve, and young men with a mechanical turn, could then look out in time for suitable places. All trades and occupations in a mechanical way would use the column after a while. Only try it long enough to be well known, and employers would find it to their interest to employ a reading, thoughtful class of men, who would not demean themselves to offer beer and bribes to foremen for a job. I should like my brother mechanics to point out any defect in such a method, if there should be one, if not, and it is tried, let them support it.

In every working man's club and library in the Kingdom, the sheet should be hung up. It would soon grow to a large sheet, and, if convenient, might be posted to employers for a yearly subscription. ARTISAN.

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small]
[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

DINORNIS GIGANTEUS.

SIR,-With reference to " Sigma's" letter, page 212, undoubtedly at present the weight of evidence is vastly in favour of Professor Owen's theory, that the Dinornis Giganteus and Dinornis Elephanteus co-existed with the present inhabitants. That they did so until a recent period is most likely, and in all probability as late as the latter end of the middle of the eighteenth

century.

The German saran referred to by "Sigma" is Dr. Haast, and the presence of "Split human bones in the ovens belonging to the Maories, together with the bones of the Moa the Kakapo, seals, &c.," as found by the Hon. Mr. Mantell, F.R.G.S., is proof positive of the existence of cannibalism. Dr. Haast bases his opinion on purely negative evidence, to some extent contradicted by the researches of Prof. Owen and Col. Wakefield, and chiefly on a point thoroughly established by Mr. Mantell, and confimed by Sir George Grey and Mr. Davison.

As Sir George Grey observes in his letter read before the Zoological Society, Thursday, March 3rd (and he is fully borne out by Mr. Mantell, and Mr. Davidson) "The natives all know the word Moa' as describing the extinct bird," also, "the natives invariably spoke to me of the Moa' as a bird well known to their immediate ancestors." "They spoke of the Moa' in exactly the same manner as they did of the kakapo, the kiva, the weka, &c., in districts were all these birds had disappeared," speaking of it in exactly the same manner as they did of other birds that had been exterminated since 1777, and that still exist in other districts.

In fact, all confirm the statement that the natives are acquainted with the bird, and uniformly assert its ex

Multiply (1) and (2) by 7 and 2 respectively, adding the istence in a recent period, and are extremely accurate products.

28 x 21 y

10 x + 18 y

14 14

= 280

= 94

[blocks in formation]

and uniform in describing its habits and appearance, even before its discovery. The name, and the ovens its remains were found in are all Polynesian, and differ from the Australians in every manner.

With reference to the Arabian records of travel, they in general are wonderfully accurate in their accounts of travels and descriptions of people, places,

Then multiply (3) and (2) by 7 and 3 respectively, sub- and events. The works of Ibn el Wardee," Ibn el

Multiply (8) and (4) by 3 and 4 respectively and tracting the products

subtract:

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][ocr errors][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

accounts.

Joassi,' and others (Papers of the Royal Asiatic Society, Jour. de Soc. Asi., &c.), show that during the 13th and 14th centuries they were perfectly acquainted with (including the politics) the islands of Sumatra, Java, Borneo, Celebes, Gilolo, Mindiano, and the Phillipines, as well as the southern ports of China. Chinese, Hindoo, and native accounts and records confirm this, and furnish independent checks on their In fact, as early as the 14th century, they had regular and firmly established stations in the Malaccan Peninsula, the East Indian Islands, Borneo, the Spice and Phillipine Islands, and everywhere the early European travellers in the 15th and 16th centuries found them permanently and longestablished inhabitants. It also must be remembered that Mahomedan, and Buddhist, and Brahman religious works establish that they carried-vie et armis, overturning after a desperate resistance the established faith-Mahomedanism into Java, Sumatra and Gilolo, although they failed in Borneo and the Phillipines URBAN. during the 13th century.

HARMONIUMS.-TO "ELEVE."

SIR. The advantage of having two keyboards over one is equivalent to that obtained in an organ where you set up two organs in one, actuated by separate keyboards, though capable of being coupled by means of an appropriate stop. One may be enclosed in a swell, and may contain stops voiced sweeter than the other, which may be called the great organ. It is the same in degree in an harmonium, and as I have described before in my resume of the two-manual professional and connoisseur's harmonium that I had, you can obtain in the stops connected with the soft manual, a degree of delicacy of tone, and also, on account of its situation with regard to the bellows, a softness of wind that is something entirely different to the effect of tone and wind that you can get in any one manual instruMore than that; the reeds connected with the soft manual may be enclosed in a swell, and thus become the equivalent of the swell of a pipe organ. Added to this, you have the increased power of combining your stops which two manuals give over one, which advantage in an harmonium is that which an amateur of taste seeks the most in order to display his executive powers.

ment.

It will be self-evident to " Eleve," that a musician seeks variety in an harmonium or an organ. If he does not, he might as well rest himself content with a pianoforte, and hammer away on his monotone without change. But even Handel had two keyboards to his harpsichord. What else did he want with two keyboards if not variety? MARK ELLOR.

TO MILLERS.

SIR,-First, I beg to thank you for such a paper as our MECHANIC is; also to thank you for the introduction into its pages of things about "dusty millers." I have read with very great interest the correspondence that has appeared in your columns, and the different opinions of the trade. Being a miller of quiet, sedate habits, I did not intend to answer any of its many important facts that have occurred from time to time. but reading a letter from your correspondent "J. S.," in this week's issue, I cannot refrain from refuting some of his arguments. First, he cannot see what use the patent balance is. I feel inclined to ask him if he ever used or tested its efficiency? I cannot believe a practical miller would condemn Clarke and Dunham's patent balances if he has tested them thoroughly and properly, no matter what sort of bearing irons he may have, or how driven. I have had 25 years' experience in various parts of England; have seen, I should imagine, every sort of irons for driving millstones; have worked in mills from two pairs to 30 pairs of stones, and have been with master millers who delighted in trying anything new, regardless of expense, for the sole purpose of securing the best way for having work in stones-driving stones; in fact, everything connected with millstone work-and I

has

challenge any man to produce a better plan for
balancing millstones than Clarke and Dunham's-I
mean, of course, running balance, because no miller
wishes to keep his stones standing still. Let us have
stones running, and we cannot do without the running
balance. As to the other part of "J. S.'s" letter, an
experienced miller can afford to pass it by, With
Thos. Evans's letter, also R. R. Smith's, I fully concur
in all they say. I should think "J. S," has tried to
balance his stones running, but has failed (as I have
known many good millers do), and in consequence
gives the patent a bad name. I advise him to try and
try till he succeeds. He will be sure to conquer if he
perseveres.
C. M.

Now, allowing barley were to be sold at 15d, per bushel, which is cheap, it is so many angels (i.e. half sovereigns); and therefore dividing it by 2, it s £236,118,324,143,482 sterling; which is in words, Two hundred and thirty-six millions of millions, one hundred and eighteen thousand, three hundred and eighty-two pounds; which I take to be too much for any tradesman to get or keep.

And reckoning land for ever at twenty years purchase, if this sum of pounds be divided by 20, the quotient is the yearly rent of 11,805,916,207,174; and this divided again by 365, the number of days in a year, the quotient is 32,344,975,918; that is about thirty-two thousand of millions a day for ever. So great a vanity may be concluded on for want of a little premiditation.

SIR,-In answer to "J. S.," p. 182, who inquires 2. Now, secondly, for the weight of it; if we put about silk dressing machines, I beg to refer him to eight bushels to weigh two hundred pounds weight, Vol. VIII, p. 222, of the ENGLISH MECHANIC, where he for sure it doth weigh more, then the whole number of will see the judgment of one who has had 12 or 11 quarters multiplied by 2, gives the weight of all to be years' experience with their working on English 944,473,296,573,928 hundred weight; and if this be wheats, and on p. 282 of the same volume he will see divided by 20, the quotient 47,223,664,828,696 is so many remarks on the same subject well worthy his careful tons; and therefore it will require 47,223,664,828 ships study. I am now dressing my flour through "Black-of 1000 tons apiece to carry it; and, consequently, if more's patent cloths," and am quite able to compete every nation in the world had above 10,000 such ships, successfully with silk-dressed flour within two miles yet there must be above four millions of such nations; on each side of me; for they cannot change their which I suppose are not to be found in this world. cloths to suit the different seasons of the year as I can. J. F.B., Chelmsford. In the winter, my neighbours' flour was deficient in strength, from being dressed too fine, and my flour was giving satisfaction, dressed through a No. 12 "Blackmore's cloth." In this month of May 1 find it necessary to use a No. 16. Now the wheat is dry, the silk-dressed flour is a trifle whiter than mine; but I can quite equal theirs in colour and quality by dressing the flour over a second time.

Blackmore's cloths are very frequently put on the reel too tightly to dress well, Ayton's net on the reel is a great advantage. Silk reels for foreign and Revitt's wheats are very much better than wire or "Bolter;" but I believe, from my experience of their use in a country mill on Suffolk wheats, that in less than ten years the proprietor would wish he had never put them up, on account of the great variation of the condition of the English wheat, and also of the different treatment that the English wheat requires in different seasons, as after a wet or a dry harvest. I suppose I may apply to myself the old, old saying, "Experience keeps a dear school, but fools will learn R. R. SMITH.

in no other."

DRESSING MILLSTONES, &c. SIR,-I have read with much pleasure in the ENGLISH MECHANIC the controversy on the question of standing and running balances in mill stones. I should now like to lay before your readers a little experience of my own on the subject. I have been using for upwards of 20 years a stone which has always had what we call a swish to it; several millwrights have attempted to get rid of it, but could not succeed. I have had three new sets of driving irons, but it made no difference. And all the millwrights I have employed have given it up in despair; such being the case, I thought I would try and carry out a notion I had as to the standing and running balance being the same. On looking between the faces of the stones when running I found the face of the stone run true at first starting, but when the stone attained its full speed it run very untrue. I then removed some of the shot from two of the balance boxes into the opposite ones, and by that means succeeded in making the stone ran true, but the standing balance was untrue to the extent of about 31b. I then started the stone again, when the heavy side dragged on the bed stone, but as the speed was increased, the heavy side gradually raised itself, and when the full speed was obtained the stones run perfectly true. I then set them to work, and since then I have seen nor heard nothing more of the swish, and the stones' work is much improved. I had previously had everything done that was suggested (except using the patent balances), and all that was done had not the slightest effect on the swish of the stone; I had a new hurst, new spur wheel and stone, nuts and new driving irons, but all to no purpose. I therefore feel quite certain that in this case

COMMERCE AND TRADE.

SIR, I am rather disappointed that my short letter
on this subject has produced so few replies, and those
all on one side. The figures I quoted were from the
"Statesman's Year-book," which goes on to draw a
dreadful picture of the fate in store for England if
her imports should go on increasing while her exports
fall gradually lower and lower.
As this conclusion
was diametrically opposed to my own, I ventured to
ask some of the clear-headed correspondents of "our"
journal what was their answer to so important a ques-
tion, and I am obliged to "Sigma," "Exchange," and
"Herbert" for the notice they have taken of it; but
our worthy "Harmonious Blacksmith" has wandered
rather wide of the subject. It is not a question of
whether the figures are accurate, or whether they
represent the real values of imports and exports. Cer-
tain figures are given, and on these fires a theory is
founded directly opposed to common sense. I believe
these figures very clearly show the opposite fact, and
your correspondent "Sigma agrees with me. The
Harmonious Blacksmith" says we cannot long con-
tinue to import more than we export, because foreign-
ers won't trust" us too much. I hope and believe
that the present state of what is called the "balance"
of trade will long continue as these figures show.
How often is it that "coin" is exported from this
country to pay for our imports? Very rarely, I think.
Merchants don't like risking that sort of thing, if
they can possibly avoid it. Besides, the fact still
remains that we actually "import" considerably more
bullion than we export. Another fact, and one your
correspondents do not mention, is that the value of the
exports is calculated at the port of "loading" the
value of imports at the port of "unloading." So that
when the cost of freightage has been adjusted, the
"balance" is our profit. It must be remembered that
7-10ths of the cost of carriage come to our pocket.

[ocr errors]

One other fact, and I have done. The three most
prosperous nations of Europe annually import more
than they export. Here are the figures:-
EXPORTS AND IMPORTS PER HEAD OF POPULATION.
Exports. Imports.
Holland.
£7 9 1
£8 12 5
United Kingdom.... 5 10 9
7 5 9
Belgium
4 16 7
615
Whether these figures are correct, and represent the
real values or no, I do not know; but surely they do
not prove both "profit" and loss," according to the
colour of the examiner's spectacles.

SAUL RYMEA.

CHOOSING ONE'S BELIEF.

[ocr errors]

ardent as to impel the owner of a "Joseph Guanerius of the true breed to allow the "Ruby" varnish to be peeled off for the purpose of undergoing chemical scrutiny. Until such a devotee is found, one must be content with the most probable solution, and it is with a view to this point that I now write.

To find a varnish which when applied (as one of your correspondents proposes) to one of two equal toned pieces of wood shall make no difference in the pitch of that piece to which it is applied, seems to be a myth, as any addition to thickness will certainly make an alteration in the pitch. Neither does the varnish by its presence contribute materially to the tone. A Guaueries violin which belonged to Spagnoletti (a former leader at the Opera) was by constant use almost denuded of its Ruby covering, yet the tone was left.

There are three distinct species of varnish which may be taken into consideration:

oil.

1st. Varnish in which alcohol is the solvent.
2nd. That with turpentine with or without drying

3rd. That where drying oil is the only solvent.
As to the first or spirit varnish, it has advantages
of being more easily made, coloured, and dried; but
the result of its application to a violin is a thin, meagre,
dry tone. I speak from having tried it on a newly
made violin, and having found that on removing it,
and using instead a varnish of the second species, the
tone was much improved; and must, from observation
of genuine Cremona violins, conclude that they were
not covered with spirit varnish.

There are many old as well as modern imitations, and one great proof of the spurious imitations is the use of spirit varnish.

Examples of the use of the third species, fat oil varnish, are to be seen in some of the violins by Albani (an old Cremona maker), exhibiting, like an old picture or carriage, the cracks and thick coat of material never seen in spirit varnish. But it is with the second species of varnish, made with turpentine and drying oil, that to all appearance the genuine violins of the Amati, Straduarius, and the Guanerii violins were originally covered; and there seems little difficulty in imitating this covering in all respects but one-viz., the colour; and to attain this, some proper colour must be found soluble in turpentine; and a query on this subject was inserted by me in one of your previous volumes, to which no answer has been given.

As far as my observation goes, genuine Cremonas appear to have had the pores of the wood filled up with some species of uncoloured size, and to have been rubbed down to a very smooth surface previously to the application of the colouring varnish; which in most of the old ones, comes off in small flakes. The same thing has happened to violins which I have varnished with the second species of varnish. But I must confess that the imitation of the clear, transparent colour is at present beyond my knowledge.

I may add that although the coat of varnish has something to do with the tone as well as appearance of a violin, yet to expect that the thick wooded, illshapen, cheap violin (call it rather fiddle) could have the tone of a Cremona, would be as reasonable as to expect a London dray horse to run round an Eclipse. One of the best makers of the day is Vuillame, of Paris. His varnish is said to be of the first species, but I much doubt the statement; whatever it may be, his models and work are firstrate.

SUFFOLK AMATEUR.

BOILER FEEDING.

SIR, The plan of feeding a boiler without a pump, as illustrated this week, and supposed to be the invention of Mr. Shewan, and as patented by Capt. Shaw, was in use in 1853 at a colour works in Lady Lake's Grove, Mile End-road. The feeder was placed in precisely the same position as shown, and worked exceedingly well. It was in this case worked by hand. You will find a patent was taken by a Mr. Beaumont, of Clapham, in 1859 or 1860, for the same thing, only to be self-acting. This I can prove by my own books, being the maker of it. It was exhibited in 1862 at the International Exhibition, where I saw it working. It was placed on a stage erected for the large injector which fed the working boilers of the Exhibition. This was made at Manchester. It is now nearly five years since I made one very similar to that of Beaumont's, which would draw its water full nothing new in the matter.

T. E, T.

SIR-Surely it does not require a great amount of a standing and running balance are not the same. clear-sightedness to see that the phrase "choose to purpose, and drew its water from the same tank as the Some of your correspondents seem to think that if the believe," in my letter on "The Rotation of the Earth,' stone will balance standing, you need not trouble your is merely a "figure of speech." To argue whether it is self about the running balance; that seems to me very possible for a man to believe anything he chooses shallow reasoning, for what is the object millers wish might open up the whole question of free will;" and to attain when trying to balance a stone? Is it not to nothing was further from my thought than that. Mr. 20 feet. My brother readers will see from this there is get an equal pressure from all sides of the stones at T. Cooke says we "must believe according to the evionce. For it must be evident to all, that unequal pres-dence presented to our senses," but he fails to perceive sure cannot turn out good work. And if the running that what we believe depends a great deal on the abibalance is untrue there must be unequal pressure. lity of our senses to properly examine and weigh the JOHN BOTTING. evidence presented to them. If everybody were capable of looking at a question "outside of himself," as it were, there would be fewer religious sects than there are, and the followers of Mr. Hampden, &c.," could be numbered on the fingers of one hand.

CURIOUS ARITHMETICAL PROBLEM. SIR,-The power of numbers in geometrical progression is very well illustrated by W. Leybourn, a mathe

As some persons believe in the theories of "Paral

MUSICAL NOTATION. from The Harmonious Blacksmith" on Hawkins's SIR,-In your number for April 8 there is a letter musical notation, in which he promises to send a familiar melody written in it. I expect he will soon fulfil said promise. All the new musical notations I have as yet had the pleasure of seeing are directed to one

metician of the seventeenth century, in his "Cursus lax, &c.," in opposition to the plain logical evidence of point-viz., the mystery or difliculty in the various Mathematicus," published in folio in London in the the astronomers-shutting their eyes to facts they do keys; and very severe terms have been bestowed on

year 1690, in the following calculation:-
A Londoner sojourning in a country market town,
in winter, made himself a new frieze suit and coat, on
which were set six dozen of buttons, of silk and silver:
a baker being in his company liked it so well that he
would buy it of him; the citizen consented to let him
have it, paying for the first button a single barley-
corn; for the second, two; for the third, four; and so
on, doubling to the last.

The bargain was liked on both parts for the present, but shortly after revoked; for it could not be performed, and no man can be holden to an impossibility. But why this could not be performed may be judged, first, by inquiring into the worth of so much barley in money; and secondly, the weight of it, and how it should be removed.

1. For the first, allowing 10,000 corns to a pint, which is more than enough; then 5,120,000 corns make a quarter; and yet, for shortening the division, we will allow 10,000,000 corns to a quarter, by which, dividing the whole number of corns, which is done by cutting off the first seven figures towards the right hand, the quotient will be 472,236,648,286,964, und so many whole quarters there are omitted the remainder, as in this case inconsiderable.

not wish to see I cannot conceive that the expression
"choose to believe" was so "decidedly wrong" as to
call for a special letter from Mr. Cooke.

and Mind."

This question of what man believes-of belief
interesting one, and I shall hope to see something
founded on "evidence," as opposed to faith-is a very
about it in the papers on "The Relations between Body
That the "body" exercises some influ-
himself says:
ence on the mind I suppose no one will deny. Byron
Who'd pique themselves on intellect, whose use
Depends so much upon the gastric juice?
SAUL RYMEA.

VIOLIN VARNISH.
SIR,-In the earlier volumes of the MECHANIC there
are a few contributions on violins, from myself and
others, in which the "varnish" has been slightly
alluded to. The subject seems on this point to again
attract the attention of your readers. It seems im-
possible to furnish proof of the materials of "Cremona
Varnish" without actual chemical analysis, and I can
hardly suppose the existence of a varnish mania so

them. These terms I consider altogether misapplied
and unmerited; on the contrary, not only are they full
of interest to the musical student, but truthful as
truth itself, the evidence meeting you both ways as
explanation it is common to explain them by making
the subject, I humbly think, might be inproved. In
you proceed from the natural or centre key of C. But
a round of the keys, by fifths, or to say so many sharps
proper places; but two things ought to be considered
or flats are required to put the semitones in their
-viz., the internal transposed, and the number of that
internal the scale contains. Let this be done, and the
difficulty of the keys will at once disappear. In addi-
tion to describing the scale as a succession of seven
sounds, consisting of five tones and two semitones, let
the more extended internals-thirds, fifths, &c.-be
examined and their number pointed out. Example-
What can be more expressive than the one sharp in
the key of G, or one flat in F, pointing as they do to
the one imperfect fifth the scale contains.
By all
means let there be improved systems, and improve-
ments in systems, but it is surely desirable to render as
plain as possible the established system of musical
notation, which is so universally diffused, and contains
such stores of music written in it.

MUSIC.

« ZurückWeiter »