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parent. They consist of a hammer and weights in different parts of my coal yard one or more lenticular disks of various de and on my wharf, I find that exposure grees of thickness and convexity. Though to the weather, and the accumulation materials of less density and more elas of dirt in the raised figures and loops of ticity, like the parts examined, are in the lifting rings, cause the weights to be some respects preferable, for greater inaccurate. When the Leet Jury visit convenience they are chiefly formed me twice or thrice a year, I am almost either of ivory or of hard and solid sure to be mulcted for some weights wood, the sonorous qualities of which being too light by abrasion or casualties, are obviated by the intervention of a whilst others are too heavy from dirt and substance affording scarcely any sound compacted coal dust. I should be thankof its own. Thus the striking surfaces ful if any of your ingenious correspondof the hammer are armed with india ents would advise me how to keep my rubber, which I have found it necessary weights correct, or devise some means of to cut into a pointed form, to prevent weighing from 1 cwt. to 5 cwt, of coal. the intervention of air between the sur by a graduated lever on the principle of faces struck, the more effectually to the steelyard. The weighing machine diminish external sound. The different must be light, and moveable on small degrees of convexity of the disks, which wheels, so that it may be removed from are formed of wood or ivory, or india one coal-heap to another with facility, as rubber, adapt them to the degree of we have sometimes three or four carts all emaciation, and consequent concavities waiting at the same time; it should also of the surfaces examined, though it is be low and flat, for the convenience of best to accustom the ear to the sounds holding the bags whilst the coals are elicited by one or two only. It is neces shovelled up. Our bags hold ten stones, sary that the disk should be firmly held, which is as much as a man can ordinarily and pressed in close contact with the lift into his cart. I have been at great skin when struck by the hammer, that expense in providing good weights and no other sounds be communicated than weighing machines, and have as many those produced by internal parts or cavi as sixty weights of 28 lbs. each in use, ties. And thus, not only within the and I am sorry to say that the rough chest may the sounds of parts examined usage to which they are exposed in the and deeply concealed be obtained with open air, with the reinoval in and out of increased distinctness, indicating the con boats, subjects me, unavoidably, under dition of the organs, and facilitating the present arrangements, to the disagreeable detection of latent disease ; but in drop circumstance of being fined by the jury; sical effusions, and some other diseases, although the deviation of the weights is I employ this percussor with interesting often to my loss, and not a dishonest effect and advantage.

gain, as some ill-natured persons are apt Having used these instruments since to infer. It costs me 8d. per weight of the early part of the year 1840, ample 28 lbs. to have them verified by the Inopportunity has been afforded of prov spector of weights and measures, who ing their advantage; and I have placed lives a long way off; and to remove such patterns of them in the hands of Mr. heavy articles in a cart has on several Waugh, of Regent-street, in the hope occasions caused them to be injured, and that they may continue to be properly to be inaccurate immediately on having constructed, and thus rendered useful to them adjusted. others as well as to myself.

What I want is a weighing machine From, Sir, yours respectfully,

for heavy commodities, without weights,

or at least but one, for coals, linseed John Harwood.

cakes, iron castings, and other bulky West Villa, St. Leonard's, Hastings,

heavy goods, weighed on the wharf. September, 1842.

I am yours respectfully,

A WHARFINGER.

COAL WEIGHTS. Sir,-Being a dealer in coals, and my trade requiring a great number of 28 lb,

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Sir,- The numerous defects to wbich Fig. 1 is a side view. Fig. 2, a secthe common ball-cock is subject have in. tion. Fig. 3 a plan, looking from beduced me to make the accompanying neath. a is the cock, which may be cast sketches of one which, I think, will be with either a round shank, for soldering, found to be free from most, if not all of or a square one, for connecting. The these defects.

mouth is curved downwards, in the usual

sand as

TAMPING WITH SAND-FIRING POWDER BY GALVANISM IN BLASTING ROCK. 297 manner, and has cast round it four square TAMPING WITH SAND, AND FIRING rods, 6 bb b, forming guides for the ball

POWDER BY GALVANISM IN BLASTING valve, c, preventing its escaping when

ROCK. not pressed up into its seat by the lever

Sir, -In doubtful matters, theories rod, d, which is jointed to an ear at e,

and opinions may be very erroneous ; cast on the cock ; to the other end of the

but facts in such cases must be of value. lever is affixed the copper float, s, which Mr. James T. Wilson, in your No. may be either a whole or half ball. A

989, treats my remarks on tamping with stop is provided at the jointed end, to

“Theory versus Practice," in prevent the lever falling so low as to al

which I think he is in error. low the ball, e, to escape from the cage,

In an interesting paper on firing 6 6 6 b, but yet sufficiently low to permit charges by galvanism in No. 978, it is the escape of as much water as the ser

stated to be the belief of Mr. Roberts, vice pipe can supply.

that “many hundred weight of gunpowThe action is sufficiently obvious, but may

der would be required to blow out a be briefly described as follows :- When

column of sand of two inches diameter the water in the cistern falls, the float, f, and 18 or 20 inches in depth, placed in will fall with it, until stopped by the stop solid rock." at e; the ball-valve, c, being no longer

I asserted on the contrary in No. 983, held up in its seat, will fall, and allow

that instead of requiring many hundred the water to rush in, as soon as it is laid

weight, a single ounce of powder would on in the pipes; as the cistern fills, the

blow out every particle of the sand. float f will rise, and raise up with it the

I ventured an opinion as to the cause lever-rod, d, and valve, e, and press the

of this fact; that opinion might be good latter tight into its seat, thereby prevent for nothing, but still the foundation was ing any more water entering. A small

the positive fact, and not a theory on cup, m, is shown on the lever-rod, to

which a result was presumed, as would receive the ball-valve, and prevent its

seem to be implied by Mr. Wilson in getting bruised.

The side view, fig. 1, calling it “ Theory versus Practice." shows the cock when closed ; and the

Now I will mention another fact, section, fig. 2, when it is open. In the

founded on numerous trials. former, the dotted line represents the In a hole of l-inch diameter and 2 level of the water when the cistern is

feet deep in solid rock, one quarter of an full,

ounce of powder will blow out every A hemispherical valve might be used particle of sand filled over that charge instead of a ball, but it would require a

to the very top of the hole ; while 3 oz. spindle and joints, to prevent its turning will not disturb a well-bammered clay round: or even a conical valve might be tamping in a similar hole; and the employed, care being taken to insure its

relative effects will be nearly the same rising truly into its seat; but the spherical in larger holes with increased charges. valve is much to be preferred.

With these facts before us, I think Sticking, which continually occurs

the presumption is that for tamping, with the common cock, (unless it is so

sand is far inferior to the tamping of clay loose as to leak,) can never, it will be or broken brick hammered down in the observed, occur with mine. The dimi.

usual manner. nished water-way, occasioned by the per

It is quite true that the effect of the exforation in the plug being so much smaller

plosion in splitting the rock is very rapid, than the bore of the pipe, is also obviated and with tolerably large charges, will in this; since, by allowing sufficient play operate in that way quicker than it can to the ball-valve, the cock will allow as

force good tamping out of the small much water to pass through it as the opening by which the charge is intropipe can supply to which it is affixed;

duced ; but where the sand shows such and the cistern, accordingly, will be filled

a great want of resistance as above in much less than the usual time.

described, it is impossible not to suppose, I remain, Sir,

but that it is incapable of procuring Your obedient servant,

the maximum effect from the explosion; E. M. J.

and in small charges the loss must be August 29, 1842.

very great.

It is not sufficient to say that great ef. moved a little to one side till after the fects are produced in blasting rock with explosion, when it was lowered again to sand tamping: the question is, would the spot for the removal of the broken they not be greater with different tamp rock, &c. ing?

The operation was in this manner carBy increasing the quantity of the ried on rapidly, and I doubt whether powder, great effects may be produced any application of the galvanic battery without any tamping at all, merely by could have been so advantageous. the resistance of the atmosphere.

I would strongly recommend no one An hundred weight of gunpowder to be deterred from the use of the fuse, placed in mass on the crown of an ordi until he has tried it well himself; the nary arch, and fired, without any load cost of trial will be small; the common ing over it whatever, will break through kind is sold, I believe, at about one halfand destroy the arch. Gates of cities penny per running foot ; that

prepared have been frequently blown in by sus for water-work, called sump fuse, at a pending about the same quantity in bags little more. The galvanic battery may against them and exploding it, as was be substituted afterwards, if it is considone at Ghuznee.

dered desirable. Thus when rocks are blasted with sand Sir, your obedient servant, tamping, the effects may be considerable,

J. F. B. and yet not so great as they might be.

It is the more easy to be deceived on this point, as the results of my experi

THE PATENT “BOCCIUS LIGHT." ence, and of many experiments, tend to show that usually much more powder is

The passing remark which we made used in blasting rock than is necessary,

on this “luminary” of the day, among and I should be glad to know by what

the “Notes and Notices in our 99th rule Mr. Wilson is in the habit of ap

Number, has led to so many applications portioning his charges of powder.

to us for further information on the subOf the superiority of igniting charges ject-from our country friends more esby galvanism, as an ordinary mode, I pecially—and to so much complaint, also, am very far from being convinced.

of unmerited disparagement, on the part I can quite understand its advantage

of the patentee and his friends, that reunder some circumstances ; but I take it spect for the reasonable curiosity of the they would be few in comparison, and

former, if not for the matter-of-course that the use of galvanism should be con

chagrin of the latter, and a regard for sidered the exception, and not the rule.

our own reputation as honest and imparMr. Wilson is quite wrong in the

tial journalists, combine to make it indis. statement, that the fuse is inapplicable

pensable that we should explain more at under water; I speak of Beckford's pa

large our reasons for the opinion we have tent fuse. There is a kind prepared ex

expressed. pressly for using under water. I have

We shall first do the inventor—if so tried it many times, and exploded powder

he can be called—the justice of laying with it, at from 25 to 40 feet under

before our readers a Report which has water, the fuse being lighted from the

been made to him, on the properties of top, and it never failed. I know of rock

his light, by Professor Brande and Mr. being blasted with it to great advantage

Josiah Parkes, with a copy of which he in from 20 to 30 feet water, by means of

has himself been good enough to favour a diving-bell, to clear a foundation for a

us, and which he seems to look upon as wharf wall. The holes were bored from

so overwhelming an affair, that it leaves the bell, and loaded each by a waterproof

pot a word more to be said ! cartridge, to which five or six feet of the Report on Mr. Boccius's Patent Gas Burn. proper kind of fuse was attached; this ers; by William Thomas Brande, Esq., was lighted in the bell, and the burning Professor of Chemistry, and Josiah end immediately passed under the edge Parkes, Esq., Civil Engineer. of the bell to the outside, to prevent the

TO GOTTLIEB BOCCIUS, ESQ. ar noyance of the vapour to the work Sir,-Having requested us to make a men. The bell was then, according to series of experiments on your newly Pasignal, raised a short distance, and re tented Gas Burner, and to report to you

}

our opinion of its merits as compared with meter; the former being considered less the burners in ordinary use : desiring also liable to accidental error, and to give more that we should pursue such methods of in. precise results than the latter. vestigation as might seem to us most advis 3rd. With respect to the means adopted able for ascertaining the quality of the light for ascertaining the relative intensities, or produced, its illuminating power, and the illuminating powers, of the several lights, we general fitness of your invention for prac

used both the method of shadows, and Protical purposes, we have to report as fol fessor Wheatstone's new photometer, which lows :

gave results in remarkable accordance with Ist. We selected as the standard of com each other; the average results of the two parison between your burners and those in methods, on numerous and frequently recommon use, the ordinary Argand burner, peated experiments, not differing more than consuming five cubic feet of gas per hour, 2. per cent. Precautions were taken for and having a flame of from 2 inches to 24 measuring the respective distances of the inches in height above the jet holes.

lights from the instruments with strict 2nd. The measurement of the quantities accuracy. of gas consumed in a given time by the dif The burners with which you furnished us ferent burners submitted to experiment was for experiment were of the following diadetermined by a gasometer, not by a gas meters, viz. :

in. in. in.

13 21 single ring
2 5 double ditto | These dimensions have reference to the
7 treble ditto

larger or outer ring. The light afforded by each of these burners confined to the use of any particular size of is of a decidedly whiter, more brilliant, and light, but extends to all lights, whether more agreeable character, than that of the adapted to the demands of a small apartordinary Argands ; qualities which appear ment, or to the illumination of the largest to arise from the more perfect combustion halls, public places, buildings and streets. obtained by the arrangement of the appara

We remain, Sir, tus of your burner.

Your obedient servants, The illuminating power of the light derived

WM. THOS. BRANDE, from an equal quantity of gas, was found, in your single burners, to be from 45 to 50 per London, August 2nd, 1812. cent. greater than the light given by the The first remarkable thing in this Recommon Argand. In the double and treble

port, which we have to notice, is, that ring burners, above specified, the economy the learned Reporters nowhere assign amounted to at least 60 per cent.; and some

any sufficient reason for the superiority experiments between your burners and the

which they are pleased to assign to the batswing, gave a still higher ratio in favour of your light.

Boccius,” over all preceding lights. It Of the fitness of your burners for the

is stated to be a valuable improvement

in the art of illumination by gas," and general purposes of illumination there can be no doubt. Their construction is so sim something is said also about

more perple, that no additional trouble or skill is re fect combustion ;" but in what "the quired for their management; and as, with

valuable improvement " consists, and a smaller consumption of gas, they afford a

how the "

more perfect combustion” is larger quantity of light, the deleterious pro effected, the reader is left to find out for ducts of combustion must, in them, be re himself. If there were really any novelty latively less than in burners of the ordinary in the construction of the Boccius lamp kind. We are also of opinion that your of a nature likely to render it preferable burners are well adapted for the application to others, why not tell us at once all of a simple and effective mode of ventilation,

about it? attainable by lengthening the central chim

Another remarkable thing is, that ney, and, by its means, conveying away the

Messrs. Brande and Parkes should have heat of the flame, and the products of com

thought of selecting, as "a standard of bustion. We cannot conclude this Report without

comparison,” by which to test the value

of the “Boccius Light," and the degree expressing our conviction that your invention is calculated to produce a valuable improve

in which it is an improvement-a step in ment in the art of illumination by gas, as advance “in the art of illumination by well as to promote its more universal adop

common Argand burner.” tion for domestic purposes; inasmuch as the This is just as if the inventor of the last economy effected by your burners is not improved steam-engine were to ask us

JOSIAH PARKES.

gas”-the

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