Abbildungen der Seite
PDF
EPUB
[graphic]

have a = - a 1 times a = a, when o is treated as

[ocr errors]

if it were a real number or magnitude. But it would not suit our purpose to follow such a plan, because we should never obtain above one root to an equation, no matter of what degree it might be, whereas it is well-known that what are called the " paradoxical" results, give us roots that answer the conditions of the questions in which the equations are involved. Thus: A number squared with 12 added, is equal to seven times the number; what is the number? Here 2-7x+12= o, divide both sides by x 4, and we have 3o. Hence x = 4, and x = 3 are the roots of the equation, either of which numbers will answer the conditions of the question. If the above equation be tested in the way that a ab = was treated, we get the same apparent paradox. Thus, let = 4, and r- 4 = o. Multiply both sides by x-3-ie., in reality by 1, and we have 2-7 x + 12 = o, divide this by x-4, and we have x-3=0, T. BROWN.

"J. N. from the North Country," query 2325, must If we beat o as same number or magnitude on both take 10grms. of iron ore, and dissolve it in hydrochlo- sides of the equation, then the paradoxical result ric, and proceed with the bichromate of potassium so- vanishes thus: a-bo, multiplying both sides by lution, as I have stated on page 605, Vol. X., save that a, we have a (a - b) = 0 x 0. Divide the first side by he must, after bringing the ore into solution, dividea-b, and the second by its equivalent o, then we

[ocr errors]

A GOOD CHEMICAL BATTERY. SIR.-That it may interest the readers of this paper, I give a description of a chemical battery which for simplicity, cheapness constant power, and durability, is the best I know of. It requires very little attention, and is always ready for use.

made of
In a wide-mouthed glass jar, having a wooden disc
a cigar box placed over its mouth, and
pendant from the board, are three copper wires coated
with gutta-percha, with their ends turned up, sup-
porting a hollow ring or cylinder of amalgamated
zine of in. thickness, the lower edge resting on the
turned up ends of the pendant coated wires, the gutta-
percha covering of the wires preventing contact of
to a wire of copper or platina passing up through the
the zinc and copper. The zinc cylinder is connected
board disc, and through a binding screw.

Suspended from the centre of the disc of wood and without touching it, is a piece of platinised silver hanging plumb in the centre of the cylinder of zinc, (sheet) rolled up, which is connected with a binding own metal; these two connections and binding screws screw on the top of the wooden disc by a piece of its constitute the two terminals.

The jar is to be filled to or its weight with a mixture of oil of vitriol of 660 by Baumé, 1 part, with 12 parts water, to not quite cover the zinc or platinised silver. The parts of the zinc and platinsed silver exposed above the surface of the acidulated water should be coated with well-boiled coal tar to protect it from the gases freed from the reaction and oxidation. When not in use the two metals can be lifted out by meaus of the wooden disc to which they are attached, and dipped into water to wash them.

With this battery as powerful a current can be had as is compatible with durability, although more powerful currents can be obtained with bichromate of pottasa batteries, but they are of short duration and varying power.

I would recommend that the cylinder of platinised silver be corrugated to obtain more surface of exposure to the acid in a small compass.

Appended is a sectional drawing of the apparatus, with descriptive reference.

A, amalgamated zinc cylinder; B, platinised silver cylinder, which should be corrugated; C, copper wires coated with gutta-percha, for holding zinc cylinder; D, binding screw terminals: E, wooden disc for supporting the cylinders; F, glass jar; G, the top line or surface of acidulated water.

AMERICAN SUBSCRIBER.

ORGAN BUILDING. in the subject of organ building I take the liberty of SIR,-As many of your subscribers seem interested sending you an idea of my own for making one pedal pipe do duty for two.

Many attempts have been made to accomplish this feat, but all of them have proved more or less useless. The prevailing idea is that of having a valve at one side of the pipe near the top, to be operated upon by the pedal key; but the great objection to this is, that the same quantity of wind which causes, say, the C pipe to speak, will prove too much for it when called overblow, or else give a different or uneven quality of upon to sound C sharp, thereby causing it either to

stated, but also to have 2 feet and 2 pallets to each pipe, Now my idea is not only to have the valve as before is it is evident that by so doing the wind for each note could be regulated to a nicety."

lu fixing the pipes, one foot would be placed over ne hole, and the other over the one a semitone higher, the action would then be thus: Ou pressing down, say, the C pedal key, the air would be admitted

through one foot and cause the pipe to sound the Cacquainted with all the top es which may have
note. On raising C and pressing down C sharp, the interested them. Intercommunication between secre-
air would be admitted through the other foot, and the taries would also prove useful in matters which could
valve at the side of the pipe opening at the same in- not be referred to in the pages of the MECHANIC. I
stant would cause the same pipe to sound C sharp. I might enlarge on the many advantages to be derived
believe this idea to be entirely o ginal; at least I have from such associations, but refrain until my fellow
never heard of, or seen anything of the sort anywhere. subscribers have had an opportunity of expressing
Will "Adept " kindly give his opinion on the subject? their views.
D. WILLIAM KEMP, Leith.
SIDDELEY.

TRISECTION OF AN ANGLE.

SIR, I beg to forward you herewith two specimens of the trisection of an angle by an original method. I should much like some of our mathematiesl correspondents to try the style of doing it, and (if accurately worked) I have no doubt they would arrive at the exact required result. The same letters apply

THE ENGLISH" VELOCIPEDE ON A NEW
PRINCIPLE, AND OUR ENGLISH ROADS.-II.
(Concluded from page 65.)

INS

24 DISHED WHEEL

X

enjoy from the reading of your MECHANIC, and I wish you every success in your arduous and praiseA THINKER, worthy undertaking.

THE "MACCLESFIELD" VELOCIPEDE. SIR,-Having been Inundated with letters requesting measuements and plan of this machine, I purpose answering all the correspondents through the medium of your admirable paper. Let it be taken for granted that it is the least fatiguing velocipede I ever mounted; can turn any corner, climb any hill, and stop instantly anywhere in coming down hill, not easily upset, very strong and firm, also free from danger.

24

C

A. Centre pin, holding front axle.

SEAT

B. Front axle, 36in. wide outside measurement.

[ocr errors]

21

E

36 STEEL STRT'

C. A block of wood to raise the plank 21in. from the ground, as the front
must be 3in. higher than behind.
E. Steering handle.

F. Hinged fork to hold steering handle in its place when going down hill.
X. Ash plank, 4ft. 3in. long, Sin. broad, 2in. thick.

SIR,-Respecting the proper use of the velocipede, I will just mention the frequently imprudent use of the same by those who are strangers to it. A friend was once using mine for the first time, and not being very strong, he almost killed himself by over exertion; let this be a warning to others. The use of the velocipede requires a training by all, especially those who are not strong. Let the following points be particularly observed at first, viz. :-Avoid trying to go fast, avoid going a long distance, and up steep hills; practice only when the roads are in good order, aim at learning the action and at going slowly; when the muscles are being sensibly developed, relinqish to both figures. Let A B C be the angle to be trisected. the exercise as soon as posOn A C mark off any three equal distances B I, 1H,sible, so as to avoid being and H G. draw the arcs FI, E H, and D G, bisect the fatigued. Go on in this angle ABC by the line K B, cutting E Hin L, mark way for a few weeks and off the distance H L on the are D G from the point G, you may then increase both the points being M N and O, join O B, cutting FI in your speed and distance. P from point Don D B, mark off DQ equal to F P, Going at it recklessly at first is the fruitful eause why some have turned away from the velocipede in disgust, and now hold it in contempt because, they say, it is harder work than walking; whereas, had they observed the above rules, and had some patience, they would undoubtedly have come to the opposite conclusion. I have considered the machine, and also its worker. I now come to the subject of roads. These three parts are included in the velocipede question. Since the railways were made and our high roads have been comparatively deserted, the question arises whether they could not be made of greater use than now? I think so. Let the Legislature be petitioned, and an Act of Parliament obtained to utilise our great high roads. Let them be asphalted, or made waterproof THE FIGURE AND MOTIONS OF THE EARTH. on the suface by some cheap and durable material, in order to avoid mud in wet weather; velocipedes could then be used whether fine or wet; or this plan: let them be divided into three parts-one side of the road for foot passengers, the middle for ordinary traffic, and the other side-say about three yards wide-appropriated exclusively for the use of the velocipede, let this part be asphalted or paved with well-dressed and well-set thick flagstones. Such a road as either of the above would be the solution of the velocipede question; just in like manner as the railroad was the solution of the use of the steam engine as a locomotive. But, it may be said, incurring such a large expense in forming the roads as above suggested would never pay. In answer, I would say, let the velocipedes be taxed. I think no one who has a velocipede will object to be taxed, provided he could get a perfect road to run upon at all times.

[blocks in formation]

In the meantime, while the above suggestion is being ventilated, let us consider if the present system of mending our roads can be improved. I think that it will be admitted by all that rain is the primary cause of our roads getting out of order, from the fact SIR,-Having been a subscriber for several years, in that it softens the roads; from this, it will be clear that everything that can be done to obviate the fact, since the commencement of our journal, and settling of rain on the roads is essential to their durahaving been the means of introducing it to several bility. I entirely agree with Sir Joseph Whitworth's friends, I may be allowed to express my pleasure at remarks, as quoted in the ENGLISH MECHANIC of the appearance of the first number of Vol. XI. I have March 11. The barbarous mode in which our roads been pleased in watching its gradual development, are mended is beyond all comprehension. What is both in importance and size, and am glad it is now the cause of the numerous holes (which are so many so generally appreciated by the lovers of mechanics, lodgments for water) on some of our roads? I was In the editorial article, "Ourselves and Our Sub- owing to a weakness in the foundation; it may be so under the impression for some time that it was entirely scribers," our talented Editor states the fact that the in part, but I believe the cause is also, and more ENGLISH MECHANIC subscribers may be considered probably, owing to the crossings of the wheel tracks as members of a vast mutual improvement society before the road is set. If a good steam roller were who consider it a duty or a privilege to instruct each other." This is so in accordance with my views hardened, we should not have such holes and unevenused immediately after repairs, and the road set or that I am prompted to make one or two suggestiousness as (to our disgrace) is so common in these enwhich I have withheld until the present, but now con- lightened days. sider it a fitting opportunity to bring under the notice of our subscribers, and to hear their opinions.

science, and art, both at home and abroad.

1. That in large towns where there may be from ten to a hundred subscribers, it would be productive of much good if they could be brought together periodically-say monthly, to discuss the many topics which have been under review in the MECHANIC during the preceding month. Then one of their number to communicate to this journal anything which might be considered of sufficient importance, for I have no doubt the Editor would willingly allocate a small portion of his valuable space to report the transactions of "The ENGLISH MECHANIC'S Science and Art Societies." Speaking for myself, I have derived so much pleasure and instruction from friendly discussions with the few subscribers I know, that I conceive, if done on the large scale, it would prove highly beneficial. 2. It would be a means of increasing the circulation of the ENGLISH MECHANIC by friends being introduced to the meetings, who would doubtless become interested sooner or later in the proceedings, and would of course take in our jourual.

But, I fancy I hear a road surveyor say, But what of the expense? Who is to find the money to repair them going on with the present system of repairing our in that expensive way? In answer. I would say, roads is carrying out the old maxim of being penny wise and pound foolish. I say, repair the roads in will, perhaps, not take half the expense to keep them the way suggested, and I believe in a short time it in good order.

I have adverted to the subject of roads because it is so intermingled with the subject of velocipedes that

the one cannot be divorced from the other; in fact, the
velocipede question is more a question of road than
one of mechanics, and I trust that very soon wiser
counsels will prevail with those to whom we look for all
progress in this respect, and I anxiously hope that, ere
long, the roads of this kingdom will be in such a
state of excellence as greatly to enhance and en-
courage the use of that most noble machine, the
velocipede, which, rightly used, tends so greatly to
promote the health of our people, to give vivacity to
re-society, to add vigour and stability to the State, and,
to bring honour and glory to our country.

3. Engineers and others who have occasion to
move to other towns, either to new situations or in the
way of business, would find a "society of friends" I thank you for the vast fund of information which
who would sympathise with their every thought, and I from week to week receive, and do from day to day

All velocipedes require good steering, which is only acquired by practice. This machine is constructed upon the principle that the driving wheel shall bear all the weight of the rider, so that the front wheels are only needed to steer by and hold the frame steady. No springs are required, nor is there any jolting. If the front axle is taken away and a small steering wheel put in its place, it would form a first-rate bicycle, which could not upset, because the levers would catch the ground. THOS. STANWAY.

-THE EARTH'S ROTATION. SIR,-My object in writing a series of letters on this subject is not to establish any new theory, but to so far combat old ones as I deem (and I trust I shall show) are not founded on fact, but are called in to existence from necessity, as an aid, to some extent, in establishing other theories. I think no one will de ny that any theory not founded on fact is injurious, in so far as it not only takes the place of what is in accordance with fact, but by a cursory examination tends in some measure to confirm or represent error as truth and so far is positively injurious to the best interests of society.

I propose with your consent to alter the form of my succeeding remarks on this subject from what ap peared in the ENGLISH MECHANIC, Vol. X, page 510, and propose to consider the whole matter under the separate heads, Rotation, Revolution, Parallax, and Gravity. These subjects are so bound up together by the modern system as to be absolutely inseparable one from another. And in connection with these subjects I also propose to notice Mr. Proctor's arguments on each as I proceed, as I deem this plan more precise and better connected, and of course will be better understood by the majority of your readers. I will, therefore, without further prefatory remarks, proceed at once to notice the Theory of the Earth's Rotation.

We are told by modern astronomers that the earth is nearly 8000 miles in diameter, which being multiplied by 31416 gives an equatorial circumference of 25132 miles, which (performing one rotation every 24 hours) gives a surface speed of 17 miles per minute for any object on such surface, but continually decreasing as we approach the poles. Our Arctic voyagers, so far as I am aware, say nothing about perceiving any difference as they approach the Arctic Circle, as it is called. If, therefore, we examine this theory closely and assist the elucidation by a diagra n, we shall find the whole idea to be simply absurd. Let N represent the north, and S the south pole. It is plain that the centrifugal force at the equator AB must be proportionately greater then it is at CD, and would amount to nothing could we esc the poles themselves (N or S. Thus, while body on one part of the earth's surface is rushing through space at the rate of 17 miles per minute, a body on the polar surface would be stationary, or nearly so; a matter it is necessary to prove before we can correctly say that the earth rotates about its axis, as it is said to do.

a

[blocks in formation]
[blocks in formation]

miles, and if he remained up one hour, to E, or 1000 miles, and so in proportion to the time he remains suspended in the air.

I need bardly say this is not so, and the idea is only tenable on the ground that the atmosphere is inseperably connected with the earth, that the atmosphere moves with the rotating earth at the same speed and in the same direction; but I am not aware that it has yet been proved to do so. How can that which floats on its surface from all points of the compass be said to be a fixture and invariably move with it?

But the double motion of the earth, that is its rotation about its axis, and its revolution about the sun upsets this argument entirely, for if the atmosphere is a fixture considered in connection with the earth's rotation, what is to become of its fixity in connection with the revolution of the earth round the sun, at a speed at which I should think even Mr. Proctor stands aghast, and which I shall eventually show is a manifest absurdity-an utter impossibility.

Even the commonest observer must know that much of the strong wind we experience in this country at certain seasons of the year is from the west, that is in the same direction as the earth's rotation, and suppose the day on which we make our observation is a stormy one, he will find the clouds carried past him at the rate of from 50 to 60 miles per hour, or near one mile per minute. But the earth is said to be accompanied in its rotation at a speed 17 times as great as our storm clouds by the air in which these same clouds float; how can this be? If it really is so, the clouds must be travelling at a speed of 18 miles per minute, inasmuch as they rush over the earth's surface at a speed of one mile per minute, while the earth rotates at 17 miles per minute, which together make 18 miles in one minute of time. Again, if the earth rotates from west to east, and a storm comes from the south at a rate of one mile per Juinute, and the peaks and valleys of the earth's surface are passing at a speed of 17 miles per minute, what would become of us? The centrifugal force generated by the earth's rotation and the wind would cross each other to such an extent as to derange the

whole order of creation: the effect must be precisely the same as of two bodies striking each other at opposite augles.

discrepancy between the work performed by the one
stop and the work performed by the four stops; al-
though the grand jeu professes to accomplish as much,
it fails to do so. An attentive examination will show
the cause of failure to be that whilst the grand
jeu" opens the four valves, it omits at the same time
closing the four little escapement valves. Thus it is
that the wind escapes so fast that the blowing be-
comes hard work to meet demands both of use and
waste. Why, then, are the escapements ineffective?
Because the large valves are not sufficiently de-
pressed to let the escapements fall and set close over
the apertures they should cover. So we arrive at the
cause of the defect-namely, that the poker or sticker
worked by the grand jeu is too short. Insert one
that shall be of suitable length, and it will perform
its work, giving results precisely the same as the
four stops for which it is intended to be a faithful
substitute or deputy.

In reply to question of "J. H." on same page.
Rivets for harmonium tongues are not of English
manufacture; would be obtained only by order from
abroad. They are needless, for a yard of iron wire
will answer for the purpose of amateurs' practice.
Manufacturers find it much cheaper to buy reeds
than to spend time on repairing them.
For tuning harmoniums ("Vibrator," page 69)
there is no royal road. It is tedious and laborious
work. The practised tuner, however, does not open
the instrument to each reed, he ascertains what half
a dozen or more reeds will require, bears in mind
which will want flattening, which sharpening, and
the degree of each, and with the catalogue on his
tablets of memory, he rectifies the lot, at once open-
ing the instrument, and by habit he can so work
with comparatively few discrepancies in results.
The finer touches are given in a final survey of the
whole.

and dejection of spirits, &c., which too frequently arise from the use of implements ill-constructed for their purpose. Communications in these pages of scientific and reliable information respecting sewing machines, from persons having no self-interest in the sale of them, may, while they advert to their comparative merits and defects, direct purchasers to the best system of construction, and so prevent poor people from being imposed upon by the delusive and exaggerated statements of unscrupulous vendors, who represent their own frequently worthless things as superior to all others. Thus, for many reasons it is desirable that the ENGLISH MECHANIC should take up this subject, and furnish in its pages practical and reliable information, which may be referred to as authoritative in the making and using of sewing machines.

This would seem to be a step in the right direction for technical education, and thus many being enabled to avail themselves of the aid and experience of intelligent practical and scientific men, may make successful efforts in improving sewing machines, which may greatly tend to their own and to the public advantage. If some of the workmen who evince decided talent in the construction of these machines could be encouraged to study and to excel in their business-if they would derive their pleasures from instructive books, instead of from demoralising drink-their own mental and physical powers would be improved, and I have no doubt that the sewing machines and other mechanical inplements which they would produce would manifest a corresponding improvement, and so may become more conducive to the pleasure and profit of all who use them. Working men may ask how it is that we cannot keep out foreign manufactured sewing machines We tak from America alone to the value of upwards of £200,000 annually, a sum that would employ 900 men at home in comfort, instead of roughing it in the colonies. We have a position, and the raw material at hand, the most convenient to make sewing machines for all the markets in the world, and ought to employ an additional 10,000 men. merchants would do their parts in selling. What is the reason we do not make? If it is simply excessive taxation, let it be discussed elsewhere; but if the misfortune be due to workshop mismanagement, it ought to be debated in these pages, to the ultimate benefit of employer and employed.

Our

Fitting up the case of a single row harmonium, as required by "J. W.," page 21, in order to accommodate two rows of reeds, will be a very troublesome affair, and to carry out the design, securing at the same time the proper working of the mechanism, will be a trial to ingenuity. The size of case must be stated before a definite opinion can be pronounced, and another matter of consideration will be the size of bellows, which it appears are already made, for it will be useless to have two rows of reeds unless there is a provision for wind supply There are many sorts of sewing machines, to proequal to the amount required for their speech under duce stitching of various qualities -some for ornafull play. A sound board for two rows will measurement, some for strength, some for heavy, some for at least ten inches in width with utmost paring light goods. Some machines are very difficult to be down of frame; one made eleven or twelve inches learned and kept in order, although an experienced will give a better character, and more fullness of teacher may prevent much of the trouble from arising. power to the 16ft. tone. The two sets of reeds are In some there is little difficulty to learn without a said to be respectively of 8ft. and 16ft. tone, the teacher, a few lessons from printed instructions being latter being an octave deeper in pitch than the sufficient to enable a person to do common stitching former, and especially desirable for sacred music. in a few hours' practice. Some machines, the most "Feeders," concerning which "W. D.," page 21, difficult to be learned, amply repay the patience bethat is to say, in horizontal position, that the feet working, and in the course of a few years confirm the makes inquiry, may be placed at bottom of case, stowed in acquiring a thorough knowlege of their may act directly upon them without intervention of truth of the adage, "A stitch in time saves nine," and levers for working. In some small instruments the that a good machine stitch will save ninety-nine. All plan is adopted, but it is not a desirable one for the machines in common use make the one-thread larger eizes, as the command over the wind is re- stitch or the two-thread stitch. The former works stricted and not easily managed. By leverage we can thread from one side of the fabric, the latter from modify the extent of throw given to the feeder, both sides. On the top side the stitching is nearly and regulate the stroke to the pressure, considerations alike in all the machines. On the under side the oneof importance when a large supply of wind is in re- thread machine forms a loop, and in a few machines a ifquisition. HERMANN SMITH. half-twist is given to the loop. One class of machines P.S.-Pendulum. I notice a statement by "Cats-interlace the two threads on the lower side. All these eye Diamond," page 45, on the sympathetic vibration chain or loop-stitches will ravel out by pulling the of two pendulums; if the pendulums, however closely thread from one end, but the two-thread stitch is hung, are attached to different supports the same more elastic aud durable than the single-thread stitch. manifestation will not arise. Professor Leslie has There are two classes of machines which make the shown that the vibration is conducted between the lock-stitch. One carries its thread from the reel in a points of attachment of the two pendulums, it passes shuttle through the loop of the needle or upper thread. along the fibre of the wood or metal rod, a pheno- The other has its thread wound in a spool, and a mena quite distinct from the sympathetic vibration rotating hook takes hold of the needle thread, and of strings excited by the mediuin of air. carries it around the spool. For strength and beauty, and command of stitch, the shuttle is the best system. The spool machine makes the least noise, and is very rapid, which advantages over the shuttle machine were at one time very great. undergone the least alteration, but the shuttle machine The spool machine has has been improved so much that it scarcely owns its and shuttle. parentage, except in the original movement of needle By reconstruction, the other parts, in some of the modern machines, nearly equal the spool machines in their quiet and speedy action. The quietness of the spool machine is very much due to the use of a curved needle worked by a rocking lever. and more liable to break than the straight needle. The curved needle is more expensive in the first cost, The nature of these sewing instruments (which will be subsequently found by a person studying them to vary nothing in principle) having been described, it will then be requisite to give patient and observant attention to the formation of the various stitches, and each distinct sort of stitch. to the action of the instruments in the execution of This being thoroughly done, the student will the more easily acquire the knowledge of a variety of constructions to be hereafter presented to him in these pages. A PRACTICAL MAN.

If the atmosphere is really a fixture in connection with the ea th in its rotation about its axis, and that both proceed from west to east at the speed just named, how shall we explain away the first and most simple principles of motion? A railway train would not be able to proceed at the same speed from east to west as from west to east, because of the current of speed assumed by the earth in its rotation. For instance, any one will try to alight from a railway train when in motion, he will find he must alight by springing in the direction of the motion of the train, or he will be brought to the ground, which would be a certainty if he had the temerity to leap in the direction of the rear of the train. This principle holds good throughout all nature. If two objects connected in motion in the same direction are not impeded in any shape, one communicates an impulse to the other in the direction of motion; but if they oppose each other, then, as a matter of course, the superior weight and velocity in the one direction will act as an impediment to the full force in the other.

SEWING MACHINES.-I.

machine are subjects of great interest to the mechanic.
SIR. The history and development of the sewing
inventive faculty and the application of mechanical
No other machine of recent years has stimulated the
skill to a greater degree. It has employed a large
amount of capital and skilled labour with great and
deserved success, and it is likely to continue to engage
for some time longer.
the attention of inventors, capitalists, and machinists
quent and numerous, that they are well known to the
The failures have been so fre-
trade, which, indeed, often evinces gross and culpable
ignorance of mechanical principles.

If the earth does rotate at this fearful speed, what becomes of the centrifugal force which must be called into existence at the equator (and proportionally as we approach the poles)? This force is a universal principle in the circular motion of all bodies in proportion to the extent of the path traversed and to the speed exercised. This being the case, a tendency in all things to fly from the surface of the globe is manifest, and it is here where gravitative attraction steps in, as it were, and presumes to settle the difficulty by applying a power controlling this centrifugal force by a power 17 times as great as the centrifugal force existing. We shall see when we come to examine the theory of gravity, at what an erroneous conclusion its Some, who are unable to invent or improve, but supporters have arrived. The centrifugal force not deserving inventors and patentees, have offered for who are fraudulently desirous to take the trade from being called in question, except as its being controlled sale worthless imitations, which have occasioned as above, it need only to be further said that indepen great trouble and expense, not only to themselves, but dent of this gravity no living thing could exist, except-also to the users of their useless productions. ing, as I have before shown, near the poles. It is a remarkable ching that some people, who think it criJOHN BEARDSLEY. minal to steal a pound of brass, will not hesitate to take by fraud what is worth more than a pound of gold-that which was produced by the hard and honest exercise of their neighbour's intellect. But as the terms of some of these patents have expired, examples of the several classes, with descriptions and drawings, will be given in these pages, so that even the amateur mechanic may be enabled to make a sewing machine, and find ample scope to exercise and display his mechanical skill.

(To be continued.)

HARMONIUM REEDS.-PENDULUMS. SIR,-To several questions on harmonium matters, I have the pleasure of giving replies, A few words will solve J. H. C.'s" difficulty (page 69), and will probably be useful to others, the defect he states being one of common occurrence. The instrument named has two rows of vibrators, consequently it has four of its stops acting directly to give speech to the vibrators or reeds; these we call register-stops. Every instrument ought to have an ample supply of wind for its requirements under the play of the fullest harmonies. The first point to be decided before testing the grand jeu "is the adequacy of the windpower when all the register-stops are drawn. We will assume this to have been ascertained in the affirmative. The "grand jeu" stop acts by interior mechanism upon the same valves that are acted upon by the exterior apparatus of the several stop-rods and levers; the defect is not in the wind, therefore, it is in the mechanism actuating the valves; there must be some

The sewing machine presents an extensive field of inquiry to the student of mechanical appliances, exhibiting a greater variety of ways to effect a definite object than can be observed in engines, lathes, or other similar structures, which, it is well known, have had longer time and more experience to be brought to perfection. The readers of the ENGLISH MECHANIC Who have the advantage of contributing to its pages may sometimes employ their scientific acquirements exposing popular errors, and showing the merits or in defects of the various species of sewing machines, and thus in some measure contribute to the welfare and pleasure of a numerous and deserving class of their toiling brethren, by rendering their tasks more facile and agreeable, and preventing the irritation of temper

BIG HEADS, BIOLOGY, AND MATRIMONY. SIR,-There is a time in every man's life when he acts foolishly; some do so, discover it, and improve, others do not seem to know it nor acknowledge it. Of the latter there is little hope of improvement, and of these two classes the world appears to be made up. I have been a reader of the ENGLISH MECHANIC for some time, and have been so pleased with the gradual improvement it has made, that I have introduced it to my workpeople.

When your correspondent "Disc" asked how it was ism and electro-biology, seeing that no one replied, I that one person has influence over another in mesmergave what I believed to be the proper answer to his heap of abuse was cast upon me instead. Fifty sumquestion, and which has not yet been refuted-but a learner, and not ashamed to acknowledge it. Exmers have passed over my head, and I am yet a perience has taught me that the man who abuses you because you differ from him is not the man that society can look to for improvement. I name this, knowing

that others are prevented from contributing to your journal, believing from the spirit already shown that abuse might follow from those who know little of the subject they oppose. Three letters appeared the week after mine, in reply to it. That of "Suburban" is caudid and respectful; those of "Saul Rymea" and "AntiHumbug," do them no credit.

In reply to "Saul Rymea," I beg to say a moment's reflection would have taught him the folly of his argument. If Lord Penzance was a practical phrenologist, it would have made no difference, as his duty is to administer the law, not to alter it. "Saul" further says that all clergymen should be practical phrenologists by Act of Parliament, thus inferring that an Act of Parliament can give a man brains, because, if all clergymen could be made so, a thing impossible, they could not prevent foolish and unequal marriages. A man may preach a good sermon, and yet not have the ability for a good phrenologist.

All progress is slow, whether to good or evil, and those unfortunate people who have to appear before Lord Penzance do not come suddenly to the unfortunate position they are brought to, but are led from bad to worse, from a look to an act; and it is for "Saul Rymnen" to prove that the attracting and repelling influence referred to in my letter has had nothing to do with bringing them into this unenviable pusition, and causing them to seek associates more congenial to their feelings and passions.

I still believe, whatever may be said to the contrary, that if young people were to follow the advice of a practical phrenologist, much misery would be prevented and fewer would separate. Here we have a married couple; did they live la love and harmony previeus to their coming before Lord Penzance? If they did, why seek a separation? If they did not, let the cause be traced to its origin, and you will find that fifteen out of every twenty were never suited for each other. One thing is certain, where husband and wife live in love and harmony, there is little fear of their disgracing themselves with those crimes that bring people before Lord Penzance.

"Anti Humbug" knows a woman who has a drunken husband, who beats her, and because he does so, he thinks my arguments do not stand good. Pray, what has this to do with the subject? I was not writing about fools and madmen-I can look upon drunkards as no better. I have heard it said that two-thirds of the men who turn drunkards after they are married are made so on account of the unsuitableness of husband and wife. I will not hazard this assertion, although I believe there are many. That the human body contains an attracting and repelling power 1 have no doubt, call it by what name you like; I call it negative und positive, and in this I am borne out by one of the first authorities of the day, Dr. J. B. Dods, who first discovered electro-biology, or as he calls it, "Electrical Psychology, or the Science of the Soul." The Doctor was twice invited to deliver those lectures before the American Senate. Many years before I knew anything of phrenology or mesmerism, I proved to my own satisfaction that the human body contained au attracting and repelling power, and was astonished when reading the above author to find that he not only bears me out in this, but clearly proves in his lectures that the body does contain negative and positive poles. The work may be had of Tweedie, Straud, London. I give a short extract in the Dr.'s words. In speaking of the Fowlers of New York and George Combe, he says, on page 41:-"They have made a righteous developement of true character in the phrenological examination of thousands of human heads; have directed the anxious parent how to train up the child of his affections; have pointed out to the sighing lover how to choose a congenial spirit of companionship for life; and have poured the light of mental and moral improvement in silvery streams on the grand Empire of Mind, yet such a science as this has been called a humbug." Again, on page 54, the Dr. continues:-" It will be readily perceived by everyone acquainted with electrical science, that if I can find an individual standing in a negative relationship to myself, or by any process render him so, then I, being the positive power, can, by producing electrical impressions from my own mind upon his, control his muscles with the most perfect ease. This is evident, because the positive and negative forces electrically and magnetically blend, are equal in power, and paralyse each other; or, on the contrary, produce motion." Again, on page 190, he refers to the negative and positive forces in man, which is too long to copy here.

small brain. If we take size as a measure of power, then we must submit that in each head the large organs will have more power than the small ones; and although two brains may be equal in size, one, from possessing a finer texture, will have a more powerful constitution than the other, always keeping in mind the temperament, which, as "Sigma" justly remarked, is the key to the whole secret. The tem peraments are distinguished, of course, by the countenance and general formation of the body. This will give an index to the natural qualities, and will be a guide to those who intend to study this interesting science.

In most cases, a person with a large brain and small muscle will naturally incline more to mental than muscular labour, whilst a person with a small brain and large muscle, if of a bilious or sanguine temperament, will incline to exert himself more in bodily labour. These remarks of course have reference to healthy brains, as the brain, like the body, may be diseased, and yet not lessened in size, but rendered almost, if not altogether useless.

I make the foregoing remarks respecting large and small brains that my words in a former letter may not be misunderstood. I now conclude, by advising young men to read "Cobbett's Advice to Young Men," especially his "Letter to a Lover." His remarks, though amusing, are interesting and really useful, and will be found not far from the mark. My time being taken up with business matters prevented this appearing sooner, and as before stated, being written amidst the noise of machinery, and at intervals, your readers will have to take it for what it is worth.

T. D., Workington.

EXTRACTS FROM CORRESPONDENCE.

the

an author,' &c. I see with pleasure that a 'F.R.G.S.' intends to send some accounts of the proceedings of his society. This would be much approved of by many readers, and add to the popularity of paper. A suggestion was also inade last year-I repeat it now-the number of re ders being much increased it might find more echo; it is that when a new produce comes somewhere on the market, one or other reader might mention it in the paper. He will be sure always to give or to receive information."

[blocks in formation]

[1836.]—ASPHALTE VARNISH.-This can be made by boiling common coal tar until it shows a disposition to harden on cooling; this can be ascertained by rubbing a little on a piece of metal. Then add about 20 per cent. of lump asphalte, stirring the same with the boiling coal tar while melting therein, until all the lumps

are melted, when it can be allowed to cool and kept for use. This makes a very bright varnish for sheet metals, and very cheap and durable. Common coal tar will not dry readily, as it is not properly boiled to expel the volatile hydrocarbons, which prevent its drying. It should be boiled out of doors, as it might take fire and burn the building.-AMERICAN SUB

SCRIBER.

(1970.]-VARNISH FOR IRON PATTERNS.—A MR. BIGGS ON ALGEBRA.-"Hugo" writes:good varnish for iron is made as follows:-Take oil of Mr. Biggs asks me, on page 35, why he used the radical turpentine and drop into it, drop by drop, strong comsign? I have not the faintest idea why he did so; mercial oil of vitriol; the acid will cause a dark syrupy he might just as easily have inserted the actual precipitate in the oil of turpentine; keep adding drops square root of 175, at least up to a few places of deci- of vitriol until the precipitate ceases taking place, then mals. He has not taken the square root of the expres- pour out the liquid and wash the syrupy mass with sion in question, for that is impossible: but he has water, and it is ready for use. Heat the iron to be certainly attempted it. I must still, therefore, beg varnished to a gentle heat, and apply the syrupy prohim to inform the readers of the ENGLISH MECHANIC duct and allow it to dry; it will be found, on being how he finds that-dried, that this varnish has become incorporated withi the surface of the iron, and therefore very permanent 175 and durable.-AMERICAN SUBSCRIBER. - Get Dr. Smith's "Principia [2167] LATIN.. Latina," Part I; Murray, price 38. 6d. Carefully learn each vocabulary a day or two before writing out the corresponding exercise. Learn the declensions and conjugations thoroughly. Make a practice of daily declining or conjugating one or more words, and by continued application Reader" will soon be able to get a fair knowledge of the language.-C. H. W. B.

175 4

2

I will not occupy any more of your truly valuable space further than to express a hope that such statements as this will not find a place in Mr. Biggs' notes on algebra."

MACHINERY VERSUS STEAM.-"A Clerical Subscriber "writes:-"Many small engines are now made to work by clockwork. Why are they not made on a larger scale? What is done on a small scale may be done on a large one. The beautiful adjustment of a modern watch may be introduced into a locomotive; greater safety would be obtained, enormous expense saved, and coals delivered to the poor at 58. a ton; besides, in the case of steamers, they would always be independent of fuel by the change. It may seem improbable, but we must remember the derision with which steam was ushered into existence as locomotive power."

SPOTS ON THE SUN.-"G. C. C." writes:"Some of your readers may not be aware that it is easy, with any good opera-glass, to see distinctly (though not, of course, for purposes of scientific observation) the spots on the sun's surface, by imply taking out the upper or lower pair of lenses, and blackening their interior surface over the flame of a candle. Several spots are now visible, and a great change in their relative positions may be observed, not only from one day to another, but if looked at at different hours on the same day."

to

THE ILLUMINATED PORTION OF MOON.-Mr. John Beardsley says: "I had overTHE looked the letter of R. L. J.,' in No. 261, until a friend called my attention to it, and although R. L. J. says my diagram helps to prove "Sigma's" views instead of my own,' he fails to show how it does so. My argument is that if he extends his thread not 33ft. I have for some few years back paid attention to only, but if he could for 33,000,000ft., he would never medical galvanism, and often found, when applying find that the plane of such distance would be truly the battery to different parts of the body, that the parallel to the higher object, simply because, as I said influence which I intended to produce was counter-before, the further he moves from the object the less acted, and when the poles were reversed, the influence will be the angle formed by moving a given distance, was also reversed, thus clearly proving that the body, until such angles would not even be discernible. as well as the battery, contains its negative and positive poles. Another proof that will bear me out, DIGITALIN.-"Pharmaceutical Student" writes:and which I think equally as strong as the last it is Many thanks to the gentlemen who have replied adinitted by scientific men that the atmosphere is Godfrey for pointing out my error; and I thank my query respecting digitalin. I thank Mr. charged with positive electricity, and the earth, as well as the food we consume coming from the earth, E. K." for his kind suggestion. I vaporised everyis charged with negative electricity. If you sit in thing that was volatile at 2120 in vacuo, air pump a current of air, with your back to it, you are almost constantly going, until not another bubble would rise. certain to catch a cold, but if you turn your face to it, No heat was applied afterwards except what it received there is not so much danger. Again, when out in from the warm acid acetic solution. Amongst our a cold day, we instinctively cover the back part of the readers who take an interest in pharmacy, and who neck, and leave the front part bare, there being an (the isolation of which I believe to be extremely have attempted the extraction of the less stable ba-es attracting force between the back part of the neck and the atmosphere; we feel the cold more keenly in the difficult), will they favour me with their result, as I at neck, whilst the face throws it off, as if containing a present have but operated on the more stable? I had repulsive power. Surely with these proofs so clearly been successful till I was brought to a halt by digibefore us it is too much for any man talis. to say I am In theory I have a universal process for the talking nonsense; if so, the author above referred to extraction of alkaloids. I should be pleased to submit has written a book full of nonsense, but it is such as it to the notice of brother students. Is there any will stand investigation. Your correspondents try to work devoted to the extraction of the vegetable make it appear as if I was led away by big heads, or large beads. If they will kindly refer to my letter, they will find no reference whatever to large heads. I mentioned large brains as taking the lead; I should have qualified it, but when I tell you that my letter was written amidst the noise of machinery, it will, in a measure, account for a slight error, which otherwise would not have occurred. The words, four kingdoms, should be kingdom,

That I may not be misunderstood, permit me to say that I endorse "Sigma's" description of large and

bases?"

SUGGESTIONS. &c.-"Henry H., Namur, Belgium," says:-"I am happy to see the continued success of our ENGLISH MECHANIC, and must tell you of the several satisfactory letters I have received from my friends to whom I had recommended it. I had the pleasure to procure a good number of subscribers, also some new contributors; all see with the greatest satisfaction the continued improvement of your publication. Recipes should be followed by the words tried,' or 'proved,' or 'extracted from such

[2180]-ENGINEERING IN GERMANY.-For the benefit of "Y. P. W.," and others, allow me to make an extract from an article by H. E. Roscoe, in Nature. He says:-" As a type of this interesting class of of Carlsruhe and Zurich, beginning with the Carlsruhe science schools, I may cite the two celebrated schools school with its 600 students. gramme, the school was declared to consist of one In the original progeneral and seven special departments. The generaldepartment, called the Mathematical, furnished instruction in mathematics, in natural science, and in modern languages and literature.' This programine has been slightly altered, and now the schools are as follows:-Duration of complete course-1. Mathematics, 2 years. 2. Civil Engineering, 24 years. 3. Mechanical Engineering, 2 years. 4. Architecture, 4 years. 5. Chemistry, 6. Forestry, 3 years. 7, Agriculture, 24 years. In Zurich exist both a University and a Polytechnic School, and although the university is a Cantonal, and the school a Federal institution, they are so far allied that they share one magnificent building, and many students of the university are, at the same time, pupils in the school. The most important department of the Polytechnic School is that of mathematics and engineering. the lectures in the Engineering Department of the The following extracts from the prospectus of Zurich school show how much more complete is the scheme of instruction there than has at present been found possible in England. B. Department of Civil Differential and integral calculus, descriptive geoEngineering (duration of course 34 years). 1st year-metry, principles of construction, practice in construction, drawing, experimental physics, experimental chemistry. 2nd year-Differential equations, technical mechanics, geometry of three dimensions, perspective, technical geology, topography, drawing, descriptive mechanical construction, surveying. 3rd year-Theoconstruction of iron bridges, railways and iron roofs, retical mechanical construction, astronomy, geodesy, drawing. In addition to these courses, there are similarly extensive programmes for the other departments. The expenses are small. At Zurich, any of the regular courses of the distinct departments or schools, can be attended for the payment of 109 franes, or about £4 4s. for the session of nine months.-C. H. W. B.

[2209.]-OVERLAND ROUTE.-If two letters are posted to India, the one via Southampton would proceed from that port by a ship which would enter the Mediterranean by the Straits of Gibraltar, and land her mails at Alexandria. The other letter, via Marseilles, might be posted in London six days later, and would go by Dover to Calais by packet, then by rail to Marseilles, and thence by ship to Alexandria, and so join the other letter. The extra threepence is well earned by the delay of six days and the extra trouble. -F.R.C.S.

[2232]-SOLUTION OF PROBLEM.-On p. 44, No. 262, for hypothenuse is divided at "8," read at " D.”—

BERNARDIN.

(2234]-COLOURED OBJECT GLASS. - I can second what your correspondent says respecting the excellence of Solomon's telescope. The red glass sent with it is not sufficiently dark; in fact, I find it impossible to use red glasses, as they are so burning hot

[ocr errors]

transmitting all the heat rays. He will find a great inprovement if he gets their revolving sun glass, with 4 different colours. Of these, the London smoke," No. 3, will enable him to look at the sun for hours without the trouble of a second glass. But the grandest views I have had of it have been with the 2 day eyepieces; these give the best idea of its size, and while showing the penumbra and faculæ, &c., give a magnificent bird's-eye view of the whole mass. For these I have had a dark glass of "London Smoke made by cutting out the brass of the ordinary day eyehole, leaving only a narrow rim just sufficient to hold the glass, so that the end of the tube is all glass. This answers admirably. Free by post 7s. The revolving sun-glass, also adapted for Venus and the full moon, is 10s. 6d.; both valuable additions to the telescope; the last will screw on the astro-eyepieces only. With this telescope I can discern easily the 3 doubles of Orion's belt-à severe test -AMATEUR.

[2270.]-MOTION OF WATER.-J. Crompton does not state enough in his query to be able to give a very definite answer. If the hole is through a thin plate in the side of a cistern or pipe, 5800 gallons per hour would pass through it, or about 929 cubic feet.Q. Q. R.

[2270.]-MOTION OF WATER.-J. Crompton must particularise, in order to get a correct answer. Is the orifice in the form of the rena contracta, and what thickness is the plate in which the hole is bored; this latter will affect the vena contracta, and consequently the quantity of water discharged. If J. Crompton has 381b. pressure per square inch, his head of water is equal to about 85 5ft., which would be valuable for many purposes, even with a quantity of water sufficient to supply only a pipe lin. in diameter.-SENEX. [2273]-TELESCOPE. Dr. Kitchener's telescope, known by the name of the " Aubert," was advertised for sale in the Athenæum of Feb 9, 1861, price £130, by the Rev. A. F. Padley, Lincoln. This is the "Beauclerc Object Glass," mentioned by "G." What became of the Doctor's other telescopes I do not know. G. J. W.

12275.]-SUN GLASS FOR TELESCOPE.-J. H. Ward will find the best glass for viewing the sun to be the neutral tint wedge, made for that purpose, and sold by the opticians. Or he can try such combination of common coloured glasses as will give the nearest approach to neutral tint, avoiding deep red, which seems to blot out detail. I find purple, green, and blue, cemented together with old hard Canada balsam (melted, and the glasses made hot), avoiding air bubbles, to answer very well, allowing the mottling of the surface to be well seen. Strips, 2in. by lin., with an extra thickness over half, in case the other should not be sufficient to prevent the light being unpleasant, or combinations with different shades of the same colours, might be desirable.-S. B.

[2275.]-SUN GLASS FOR TELESCOPE.-Any coloured glass, sufficiently dark and clear, may be used to view the sun, or even a piece of smoked glass. More costly eye-pieces for this purpose are made by optician. If no other protection than coloured glass is used, the observer should contract the object-glass to 2in., or he may injure himself very seriously. Throwing the image of the sun on a sheet of white paper, held at a proper distance before the eye-piece, is not a bad plan. [2282.]-POWER OF STEAM.-The 32ft. length of steam pipe will not cause much loss of pressure if the pipe is well covered and protected from condensation. providing that the pipe is not of a very small diameter, as then the friction would be sufficient of itself to reduce the pressure materially.—Q. Q. R.

-G. J. W.

[2283.)-PAINTING SCENES.-The best way to paint theatrical scenes is, 1st, to sew the calico together, 2nd, melt some glue so that it will be as liquid as possible, then mix the common paint used with oil, with it paint the scene and leave it to dry for about one hour. It won't crack, and no varnish need be used.-H. GARLAND.

[2290.]-BROAD PENCILS.-Winsor and Newton sell the pencils with broad oblong leads.-G. E. CRICK. [2291]-THEOREM.-In answer to "E. W. V.," I

3

would say, let him make an ellipse, the circumference
3+2
of which is
+31416 78540 area = 3 x 2 x
2
7856 47124. Diameter of circle with same per.
= 24. Area of circle = 22 + 785 = 4908750.-
W. STEPHENSON.

240 cubic ft. per minute will, by it, give 12 to 14 h.p. Pressure no object.-J. C. SHEWAN.

[2327.)-READY RECKONER.-The best one published is by W. and R. Chambers, called "Commercial Tables," in which he will find everything he requires.

[2328.]-DEFECTIVE GUTTER-If "Salop" were to brush over his cast-iron gutter inside (when perfectly dry, and with the rust scraped off) with hot boiled gas tar or hot pitch, I think that the "weeping" through the metal would be effectually stopped. - Q. Q. R. [2330.]-BOOMERANG.-The boomerang is a wonderful weapon, but it takes years to bring a man into the knack of proper use, "Et le jeu ne vaut pas la chandelle."-G. E. CRICK.

[2298.)-REMOVING OIL PAINT FROM SILK.
-If "Cantab" will make a strong solution of com-
mon soda and hot water, apply hot with a brush
several times over, then rinse well with cold water,
he will find it answer his purpose.-W. W.
[2299]-GENERATION OF ELECTRICITY-If-W. STEPHENSON.
"Lancashire Lad" will take a piece of iron tub hoop,
about 4in. long, bend it in the form of a clamp
and force one part between the iron framework and
woodwork at the end of the carriage, the other part to
rest on the brasses, or, what we call, tops, you can
screw it fast to the spindle box, one end to touch the
brass, the other to touch the iron work. It has never
been found to fail where properly applied. The cause of
electricity is the high temper of the spindles and speed
-SELF-ACTING MINDER, Blackburn.
[2304.]-PALO DE VELA.-The Spanish word
"Palo," means a wooden staff, a mast, and when
joined to another word, tree or wood; Palo de tinte, dye-
wood; Palo de Fela, candle tree or candlewood; but
this candlewood is not the same as the candlewood of
Guiana and the Antilles; this latter is so called be-
cause it is used by fishermen during the night. The
"Palo de Vela receives that name from its fruit,
which is 3ft. long, and candle shaped; a note on that
fruit has just been published, p. 45, No. 262, of our
ENGLISH MECHANIC, extracted, I believe, from
the French review Les Mondes. Botanical name is Par-
mentiera pendulus; the genus Parmentiera is an unde-
termined genus of Gesneriacea, near the genera Cres-
centia and Bellonia. The candlewood from the Anlilles,
&c., comes from Amyris sp. (Toxifera ?) Burseracea
The name of candlewood is also given in Guiana to the
wood of Toulicea Guyanensis, Aubl. of the soap-order or
Sapindacea; perhaps it is also used for lighting
purposes.-BERNARDIN.

[2306.]-MORE STEAM WANTED.-I think the
boiler of "D. C. W." large enough for the size of his
cylinder, and if he would only be at the trouble to turn
the exhaust steam into the chimney, he would find it
act as a good steam jet, and would cause a greater
draught on the fire, consequently making more steam.
-F. W. W.

[2306.]—MORE STEAM WANTED—If “D. C. W." puts (as he suggests) four or five tubes round the smoke flue, he will probably get steam enough, but there is danger of superheating the steam so much as to make it act injuriously on the cylinder, packing, &c., so that I think the best plan would be to put in a few "Field " tubes from the roof of the fire-box. They are very effective, have good circulation, and I believe that all information about them can be obtained from Mr. Lewis Olrick, 27, Leadenhall-street, London.Q. Q. R.

[2311.]-NEW WORM IN VICE BOX.-"A. E. B." should bore the old worm out of his vice box, and at the open end insert a cast steel bush, cut with a good thread to fit his screw, and fasten it with a pair of small but strong screws, let in countersunk holes; by doing so, he will, with care and oil, find it better aud easier than a new box and screw.—TANGENT.

[2311-NEW WORM FOR VICE BOX-To braze the screw in a vice box, or any inside work. Having twisted your inside thread round the screw, file and fit till it reaches the bottom of the screw box, taking care not to drive it in too hard, and make two marks, to enter it always the same way. Having driven it home, make a lute of clay and ashes, and cover the box with it (the screw part), but not much more than one-eighth thick-the reason of this is to prevent the brass running too soon, and also to protect the box then turn out your screw and put in some powdered borax, shaking it well about, then put in about 1 oz., or 14 oz., of brass binding wire in a flat bank, reaching from top to bottom of the box, take it in the tongs by the closed end and secure with a coupler, and having a good fire ready, put in the box, and gently turn it round for the clay lute to harden, occasionally taking it out, then let an assistant urge the fire till the box becomes of a bright cherry red, and turn it round constantly. When the wire runs, a blue fire will come from the mouth of the box; when you see this, uncouple the box and roll it round on the floor, to distribute the braze, till it goes down to a low red. Having prepared your strip for the inside screw, just enter it in the thread of the male screw and pinch both in the vice, tapping it down into its place with the hammer, and turning the screw round occasionally to nip it in a fresh place, till it is all gathered, then proceed as above.-G. E. CRICK.

[blocks in formation]
[ocr errors]

[2335.]-CONTACT BREAKER.-E. Tucker should make (if a good amateur) or buy one of Rhumkorff's double quicksilver contact breakers, as the only expense connected therewith is the evaporation of it small trifle of spirits of wine. He will not only find a increase the power of his coil, but find it a deal more manageable than the old spring and platinum point breakers. If he requires it, I will send a small drawing and description of it, as it is an instrument that has only come up just lately, and I have not heard of any in England. A coil that gave formerly only a spark 9 centimetres long, was increased nearly 60 per cent. with a quicksilver instrument.-TANGENT. [2336.]-BRONCHITIS.-" A Three Years' Sufferer" will only get rid of his affliction by change of air. As to its degenerating into consumption, there is no fear of that, if there are no other concomitant circumstances, such as hereditary or other predisposition, &c. I cannot refrain from expressing an opinion that it is highly undesirable to open the columus of the ENGLISH MECHANIC to questions of prescribing, as it offers the opportunity to the uninformed to perpetrate an infinite deal of mischief by the recommendation of their nostrums. A remedy which is useful in one case, may be hurtful in an apparently similar one.-F.R.C.S.

[2337]-STEAM INDICATOR.-The work recommended by the Science and Art Department, in their examination, is by Main and Brown; Longman pub

lisher.-W. STEPHENSON.

[2346.]-GEOLOGY.-The works edited by Ansted, Jukes, and Haughton, are all good, and are used at the examination as text books.-W. STEPHENSON. [2346.]-GEOLOGY.-"Permian" will find these two books the very best, "Introductory Text Book of Geology," illustrated, 7th edition, 28.; "Advanced Text Book," 4th edition, 7s. 6d. Both works by David Page, LL.D., &c. Win. Blackwood and Sons, Edinburgh and London. There is also a "Handbook of Geological Terms,' "7s. 6d., same author and pub. lishers.-BUSY BEE.

[2350] RAISING WATER. The cheapest, and even best, way, is by the simple suction pump, with not less than three clack-valves in the suction pipe. Any plumber will put such a one in for you.-SEÑEX.

[2360.]-ALUM.-The shale is slowly roasted in large he aps, so as to oxidise the pyrites or sulphide of iron it contains, and generate sulphuric acid, which unites The shale is then placed in large pans, sunk usually in with the potash in the shale, and also with the alumiua. the earth, and lined with lead and fitted with steam pipes; here it is boiled with sulphuric acid, till as much as possible of the alumina is dissolved. The liquor, at the proper state of concentration, is then drawn off and mixed with sulphate of potash, which is usually obtained direct by acting on chloride of potassium. Alum is generated, and being far less soluble than the salts it is derived from, precipitates in fine grains, the liquid being well stirred during the cooling. These small crystals are then washed with cold water, and then dissolved at a boiling heat, and run off into vats to crystallise. A very large proportion of alum is made with sulphate of ammonia instead of potash, which is obtained from gas liquor. Ainionia alum is £2 a ton less value than potash alum, but is seldom so free from iron, and is useless for several of the purposes for which alum is employed, such as satin papers -SIGMA. the preparation of paper hangtugs, especially the white

[2360.)-ALUM-The old way of extracting alum from shale, was the following:-The shale was first exposed to the air, when the oxygen of the air, assisted by moisture, effected a wonderful change in it. The original hard stony substance became split up into thin leaves, and became studded over with crystals. When the alum shale thas weathered was digested in water, sulphate of alumina and sulphate of iron were dissolved out; this solution was then treated with chloride of potassium, which decomposed the sulphate of iron, forming sulphate of potash and chloride of iron. When this liquid was evaporated to concentration, and allowed to cool, crystals of alum became separated. The crystals thus obtained were not, however, free from iron, and therefore required to be re-dissolved in water, re-concentrated, and recrystallised. The same operation had to be repeated As the a third time before the alum was pure. weathering of the shale took some years to proceed, a more expeditious method had therefore to be resorted The shale is now broken up into fragments and wood being set fire to, the coaly matter of the shale begins to burn, and the whole ridge undergoes the process of roasting; the results of which are the same as the weathering operation. This material is afterwards worked up as above described.-MINNEHAHA.

[2321.]-SWAN PROCESS. I believe that the Autotype" Printing Company, 36, Rathbone-place, Oxford-street, London, (who possess the patent right of that process), have just issued a manual of autotype [2296.]-COPPER DIE.-Take a piece of clean cop- to obtain the information he requires.-Q. Q. R. printing, from which "Scribo" will probably be able per, and having heated it to a blood red, place it in a strong iron ring on the anvil, and hold the die over it of water per minute in lbs., by the height of fall in [223]-WATER POWER.-1. Multiply the quantity whilst an assistant strikes a blow with a sledge ham-feet, and divide by 33000, the nominal ".p. The per The copper will be found to be an exact counter- centage of useful effect will, of course, differ accordpart of the die, if this has been carefully and quickly ing as the wheel is more or less perfect, For example:- piled up over brushwood in long ridges, and the brushdone.-CHIP.

mer.

[2296.]-MONOGRAM DIE.-" Cantab" will find it the best plan to electrotype his copper counterpart on his steel die By-the-bye, this counterpart has strangely received the misnomer of a "matrix." which term obviously belongs, of right, to the sunk die.-F. R.C.S. [2296.]-MONAGRAM DIE.-The copper matrix is not cut, it is stamped or cast.-1OTA.

2

[2297.]—VIOLET INK.-I forward two recipes for "Cantab's" benefit:-1. Boil 8oz. of logwood in 3 pints of rain or distilled water to 1 pint; strain, and add 14oz. of clean gum (Arabic), and 24 oz. of alum, in fine powders; agitate frequently until dissolved. Cudbear 1oz., pea lash 14oz., mucilage (gum Arabic), 2oz, soft water to make a pint; pour the water hot on the cudbear and pearlash, allow the mixture to stand for 12 hours, then strain and add the mucilage; 10, of rectified spirit may also be added.-EDWARDUM A.

Breast wheel, 60 per cent.
Useful effect Overshot ., 65 to 70.
Turbine 75 to 80 (with so small a
quantity of water and so small head, I cannot recom-

[ocr errors]

mend turbine in "G. P.'s" case).

N.B.-As "G. P.'s" is a very elementary one, per-
haps it will be necessary to inform him that one c. it.
of fresh water, weighs 624lb., hence, in his case,
62lbs. 4 × 203 c. ft. x 7ft.
=264 horse power.

33000lb.

2. The volume of water behind the dam, will have no effect so long as the quantity escaping upon the wheel and the height of fail is the same.-SENEX.

[2323.]—TURBINF.—If “ G. P." can have a dam 7ft. high, he can work my turbine to great advantage, by having the spout fixed in the top part of the dam; 1

[ocr errors]

[2370.]-UNSOLVED PROBLEMS.-No saving of power would result from the use of J. Bannell's invention, however smoothly it may work, since no power is lost through the present mode of obtaining rotatory motion from the reciprocating piston. Many elaborate and ingenious mechanisms have been devised to obviate the use of the crank, from the most erroueous notion that the crank causes a loss of power. But it will be a very difficult matter to find any more simple or efficient contrivance for the purpose thau the crank, aud I would advise J. Bannell to spend neither time nor money in further developing his invention.-W. H. N.

« ZurückWeiter »