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justifying process; but the advantage of small eccentric or cam (working at the Captain Rosenberg's machine over that end of each groove) it is instantly pushed of his rivals, in respect of celerity, must forward, for the purpose of giving room for the present be considered as reduced, for the next type to fall down. by the justifying process, to the differ In this manner the types are distrience between 6,000 and 9,000 an hour ; buted and arranged into lines, all the leaving still, however, a gain of 50 per a's in one line, the b's in another, and so cent.

on, ready for being replaced into their

corresponding compartments in the com2. The Distributing Machine.

posing-machine. This operation of reThis machine, represented in fig. 2, placement is performed through the meis quite detached from the other, and dium of an instrument, denominated worked independently of it.

the feeding-stick,” by which 200 or a is the galley into which a portion of 300 letters may be lifted at once from the the page or column of type, after having distributing machine, and transferred to been printed off, is transferred.

the composing-machine. b a travelling-carriage, into which the The number of letters which a lad, lines are lowered from the galley a, line with the aid of the machine, can distriby line, by means of a slider with a bute, and replace in the composing-mahandle on it, (seen at the top of the gal- chine, is only 6,000 an hour; but this ley). From this carriage, the different would offer no hindrance to the general letters are distributed, by the action of operations of any printing-office adopting the machinery, into separate receptacles the system of composing by machinery, provided for them.

for there might be as many more distric are keys, with the letters of the al

buting-machines employed than comphabet engraved upon them.

posing-machines, as the relative speed d a box, fixed to the end of the tra

of the two required; for instance, three velling carriage, containing a convolute of the one for two of the other, five for spring, by the effect of which the line of three, and so on. type in the carriage is continually pressed The cost of Captain Rosenberg's two against the front of the carriage, until machines must, we think, be greater than the last type in the line is delivered. that of Messrs. Young and Delcambre's

e grooves, made in an horizontal plate, one; but on this point we are without into which the types are received, when the data requisite to enable us to speak distributed from the carriage b. In these with confidence. Captain Rosenberg grooves the types are formed into long himself is of a contrary opinion. The lines, (one sort of letters in each line,) machines now shown at work (9, Howby the revolving motion of a small cam ard-street, Norfolk-street, Strand) are or eccentric, working at the end of each the first complete ones of the sort, and groove. (This part of the machinery is what they may have cost furnishes, of necessarily omitted in the engraving.) course, no criterion by which to judge of

A line of type having been lowered the price at which they could be manufrom the galley a, into the carriage b, factured in considerable numbers for sale, the distributor takes hold of the handle on this carriage by his right hand, and moves it towards the right. He then reads the line over, and having, by the forefinger of his left hand, raised the Sir,- Although this subject has, in key belonging to the letter, which now some degree, engaged the attention of is nearest to the front of the carriage, he philosophers, yet it has not got so large a moves the carriage to the left, until it is share of their consideration as it merits. stopped by the action of the key he has To the action of air, in its various conthus raised. The effect of this is, that ditions, I am persuaded all the phenothe letter corresponding to that key mena of heat, electricity and magnetism, is, through the machinery, forced out are referable. It is not necessary to have from the line, and falling down through recourse to the imaginary agent called a recess which is made to receive it, is heat, to explain the effects produced by guided into its own groove in the hori fire: they, evidently, are caused by the zontal plate e, when by the action of the action of atmospheric air, and its seve

ON THE ACTION OF AIR.

ral modifications, coming under the de. come from the battery, pass through the nominations of combustible gas, and gas conducting wires, meet in the connecting which supports combustion.

It is as

wire, and there, by their concurrence, clear as two and two make four, that the and the pressure arising from it, produce effects of the burning-glass are produced the fire perceived. If the ends of the by the joint action of solar light and at conducting wires be dipped in water, mospheric air; and that, the combustion aëriform Auids or gases, called oxygen originated by the lens will proceed with. and hydrogen, come from them, which out the aid of solar light, and by the ac are supposed to be, somehow, formed tion of the atmosphere alone. No com from the water. With this opinion, how. bustible thing can be ignited in the ab ever, I do not agree. I think these gases sence of air. Gunpowder cannot, by any are derived, mediately or immediately, means, be exploded in vacuo. I have from the atmosphere ; that they are but seen the finest gunpowder lie on a red modifications of that element; and that, hot wire, in vacuo, until the wire melted; they come from the battery, through the without either exploding, or igniting, or conducting wires. I think so, because being, in any way, perceptibly affected. the fluid appears to issue from the wires, And I have seen the same gunpowder and is susceptible of diversion at any part taken out of the receiver and exploded in of them; because, atmospheric air can be air, by the remnant of the same wire, sent through many kinds of wood and ignited by the same galvanic battery-for stone by atmospheric pressure alone; and that was the source whence the fire was because, all metals prepared by fire, such derived. If the vacuum be imperfect, as copper, steel and iron, necessarily are that is, less complete than it might be, saturated with air. (for a perfect vacuum is unfeasible,) the The ebullition of boiling liquids is gunpowder, after being in contact with caused by air which comes through the the connecting wire for a while begins to substance of the vessel in which the li. smoke and burn; effects which are caused, quid boils. If a common drinking glass partly by the air in the receiver, and be immersed in a vessel of oil, and the partly by the air which issues out of the mouth be then turned downward in such wire. Gunpowder may be exploded un a manner as to exclude all air from the der water, if a sufficient quantity of at interior of the glass, and leave it occumospheric air be put down with it; but pied by the liquid, and the vessel be then no explosion, under water, can be had put on the fire to boil, the air will grawithout air. If a little gunpowder be put dually drive out the oil, and take possesin a glass bottle, and the bottle be then sion of the glass. The result will be the corked and sunk in water, the powder same, if milk, or water, or, I apprehend, may be exploded by light; that is, by a any other liquid that will boil, be used inlens. But if the powder be put in the stead of oil. bottle, and the bottle be then filled with By compression, air produces the pheflour, or fine sand, firmly rammed down, nomena of light and heat; for instance, so as to exclude all air from the powder; the sparks from percussion arise from the and the bottle be then corked and sunk, compression of atmospheric air in the the powder will not explode; nor can it parts of the substances brought into conbe ignited. Now these facts clearly prove tact by the percussion. The radiation of that, the noise, the concussion, the fire the spark, is an action whereby the conand light, and the disperson of matter, densed air recovers its equilibrium; and which accompany, and, in fact, constitute, the effects which the spark is capable of the explosion of gunpowder, are produced producing, are caused by that radiation. by an action or operation of the atmo This is proved by the fact that sparks can sphere.

be obtained only from percussion in air ; It may be asked, if air be necessary to or from substances saturated with air. ignition, and fire be air in a state of ra From flint and steel, which produce an diation, whence comes the fire in the abundance of brilliant sparks, when struck connecting wire of the galvanic battery, in air, no spark whatever can be obtained in the exhausted receiver, where it will in vacuo.

This is shown by screwing be said, there is no air ? The answer is,

the lock of a gun to the plate of an air that it arises from the confluence of the pump, exhausting the air, and drawing two columns of aëriform fluid which the trigger. All substances, at the earth's

put in

as to ex

surface, are saturated with air, and some AN IMPERIAL BUSHEL OF SOVEREIGNS. of them, such as agate and quartz, are Sir,—The beautiful new sovereigns of extremely tenacious of it; but it may be the present reign, being fresh from the extracted from them. Two pieces of Mini and of uniform thickness, a good apagate or quartz, rubbed together under proximation may now be made, to what water, give out light by a sort of corus

may be termed an imperial bushel of socation ; which arises from the compres vereigns. sion of air in the angles and parts of the Those acquainted with geometry will substances brought into collision by the readily see, that if a sovereign be laid operation. For, if the substances are down as a centre, six others may be placed

a vessel of water, about 18 around this, so that the six shall all be in inches deep, covered with a lid, and contact with each other, and also with the placed in a dark room, so

centre one ; after this, if other circuits of clude every ray of light, and thus kept sovereigns continue to be laid round, for four or five months, the water will placing segments between segments so saturate them, and expel the air from

that no spaces are left but the small trithem, and they will then afford no light angular ones between every three soveunder water. If, however, light be ad reigns, the arrangement will be that of a mitted to them, while in the water, they series of concentric hexagons, each cirwill continue to give light.

cuit exceeding the last by six in number, Iron and steel, from the method of and the hexagonal form becoming more preparing them, seem to be saturated beautifully developed the farther we prowith a species of hydrogen; hence, we ceed from the centre. may understand how they burn in oxy Let us then assume this hexagonal gen: namely, by the union and ignition form as the most proper one for our of the two gases.

bushel, and taking the following series, Animal radiation, or animal heat, as it 1 + 6 + 12 + 18+. 24 +30 + 36 +42 + 48 + is called, seems to arise from the com 54, we shall obtain 271 as the area of the pression of air in the lungs.

bushel in sovereigns. In the above arSolar light appears to be the power rangement, we shall have 19 sovereigns which moves the earth, both on its axis, in a straight line, from any angle of the and in its orbit.

bushel diametrically across to its opposite In support of these views, allow me angle, and these 19 sovereigns will meaalso to refer to the following papers in sure 16:36 inches in length; but as the the Mechanics' Magazine, viz., a paper sovereigns at each end of this line will “On the Action of the Atmosphere," not fit into the angles of the bushel, we signed W., in No. 698, vol. xxvi.; a must take twice the .07 and add to 16:36 paper " On Heat, the Action of Light making 16.5 inches, which will be the and Atmosphere, and on the Distribution diameter of the circumscribed circle, the of the Atmosphere over the Earth's Sur. half of which, or 8.25 inches will evi. face," signed W., in No. 716, vol. xxvii.;

dently be the side of your bushel. a paper

- On the Action of Light and That this bushel of 8.25 inches in the Air, and the Distribution of the Atmo side may hold imperial measure, its depth sphere over the Earth's Surface,” signed must be 12:544 inches, and I find it will W. in No. 800, vol. xxx.; a paper take 203 sovereigns laid flat together to Vaporization," signed W., in No. 821, fill up this depth ; therefore, 271 ~ 203= vol. xxxi.; a paper

" On the Action of 55013, the total number of sovereigns Light and Air, and the Distribution of such a bushel will hold, the Atmosphere over the Earth's Sur. In the proportion of breadth to depth, face, signed W., in No. 921, vol. xxxiv. ; this bushel will be found to vary but litand especially to the last of them, and to tle from that in common use for the measay that they are my papers.

surement of corn, and perhaps it will be I am, Sir,

proper to state also, that my measureYour most obedient servant, ments were taken with a scale beautifully G. WOODHEAD.

divided to 100 of an inch by an eminent

London divider. Mottram, near Manchester.

Should there be found to be any origi. nality in this calculation, perhaps you will do me the favour to give it a place at

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a - n

LIFE ASSURANCE.

van

Ra

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ar

whole duration of life, then Sir,—The equation or formula which

1 1 I gave in No. 921 of your excellent ishes, and P

(6 + 1.) These Journal, for finding the present value of one pound, depending on any age, for any short period, (not exceeding ten

theorems are much simpler than those

given by De Moivre himself, and it may years where great accuracy is required)

be observed that they are strictly true and for any rate per cent., I now find

when the decrements of life are constant. may be much simplified, and at the same

The letters a, R, r, and n have the usual time made to give a nearer approximate signification, and w is the present worth value of P. The theorem is,

of an annuity of one pound for n - 1

d 1

years. The demonstration of the theo. d (w + 1) + P

R

rems is very simple, and is as follows.
Assume

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ar

8

+

+ &c., to and

8

a

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nd

8

Rn+

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$

(a

a

d a - 2d a – 3d

+ R R2

R3

R-
d
a2d

a

- n d

+ + &c.,
R

R?
RE

Rn + 1
Hence, by subtraction,

d

1 1
d
+

&c.,
R R

R R3 R+

1 1 Consequently, 8 =

d - d +

+
R R3 R-

R-
1 1 1
But

+ &c., to is the present worth of an annuity of one R R? R 9

R" 1 pound certain, for n 1

years, and is therefore given in the Tables. Let it be re-
1

-nd cognized as w; then s =

d - dw

, R.

1 d

d (w + 1) + R"

Ꭱ .

Q. E. D. Example 1.--Required the present worth of an annuity of 11., depending on the life of a person aged 20, for 7 years, interest 5 per cent-probabilities from the Carlisle Tables, and the first payment in advance.

Here d = 42), n = 6, W + 1 = 5:3294;
R" – 1:340095, nd 5836 and a = 60 90, = .05 ;

5836 1

= 4.9572

1:340095/304.5 .. 4.9572 + 1 5.9572 is the required value, which, by another method, we find to be true in every figure.

Example 2.—Required the value of an In this case a = 86 – 36 = 50, the annuity of Il. on a life aged 34, accord complement of life; and w + 1 = 22:34 14. ing to De Moivre's Hypothesis, rate of Hence P 25 – * (22.3414) = 13.8293. interest 4 per cent.

The present value of ll. by the Car.

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lisle Table, for the same age and rate per with the exception of the values on very cent, is 15.856.

young or old ages. If, instead of 86, we De Moivre supposes 86 years as the take 96 as the maximum age, the results maximum limit of life; but the value of will be more in accordance with the Carlife annuities computed from this hypo lisle Table, which, with some slight mothesis gives results even lower than those difications, is now used in many of the deduced from the Northampton Table, London Assurance Offices. Table showing the Values of an Annuity of ll. on a single life, according to De Moivre's

Hypothesis, and De Moivre's Hypothesis Modified; also, the Northampton and Car. lise Tables : interest 3 per cent.

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SPONTANEOUS HEATING OF CAST IRON. Sir,–With regard to the spontaneous on exposure to the atmosphere : one heating of cast iron, several instances are third was converted into a mass very like reported; for instance, Professor Daniel, plumbago. Mr. Dean raised some cast-iron in examining a cube of grey cast iron, by guns and balls on the June 16th, 1836, from muriatic acid obtained a porous spongy the Mary Rose, sunk off Spithead, July substance; untouched by the menstruum 18th, 1545, which became very hot and fell it was easily cut off by a knife, had a dark to pieces. Balls of 30 lbs. were reduced grey colour like plumbago, and when to 19.8 and 70 lbs, balls to about 45 lbs. placed in considerable quantity on blotting Perhaps some person would inform us, paper to dry, it spontaneously heated, through the medium of your Journal, ignited, and scorched the paper : its pro whether any similar phenomenon has perties were not impaired by being left been observed with regard to the cast iron for weeks in the solution of iron or in raised from the wreck of the Royal George, water.

and if so, what is supposed to be the Mr. D. Williamson, in his work on cause, and the chemical action that takes Engines of War,states than an iron gun place. Is it that the heat becomes susof the Florida, of the invincible Armada, ceptible by reason of any sudden consunk off one of the western islands of traction ? Or does the cast iron become Scotland (Mull) when raised by Sir Arch minutely divided, and therefore its af. ibald Grant and Captain Roc in 1740, finity for oxygen so much increased as to became red hot in less than a quarter of an take fire in the atmosphere ? hour, and was cool in three hours; also I remain, Sir, your obedient servant, that a gun raised off Carlscrona, having

I. K. F. been in the sea 50 years, became very hot October 20, 1842.

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