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ELASTING ROCKS UNDER WATER BY GAL

TUS INVENTED BY DR. HARE.

MECHANICAL CHIMNEY SWEEPING. A slight attention to these points will Sir,-Public attention has been very

ensure the efficient and cleanly execution properly directed to a somewhat im

of what has heretofore been very imperportant matter in connexion with the fectly accomplished by a very barbarous forthcoming emancipation of the “ little

method. negroes of our own growth,” by the

I am, Sir, notice which appeared at page 425 of

Your obedient servant, your last volume.

WM. BADDELEY. The change which will then be com

January 3, 1842. plete, has already to a great extent taken place; machines are now become common, children scarce. Thanks to the inde.

VANIC IGNITION.-IMPROVED APPARAfatigable exertions of Mr. Stevens, and his humane coadjutors.

(From the Franklin Journal.] Lest the compulsory humanity which

In Vol. xii, of the last series of this Jouris now thrust upon us, should be productive of needless annoyance, I beg to

nal, (page 221,*) we published an article by

Professor Hare, describing an apparatus for add a few words for the guidance of

the blasting of rocks by means of galvanic housekeepers, on a point upon which ignition ; and it will be seen, by the subthey are open to deception.

joined letter, that Captain Paris, a wellThere are at this time in use two kinds known engineer and architect, of Boston, of machines for sweeping chimneys, has applied the proposed means, with per. known as Smart's and Glass's. The fect success, in blasting rocks under water. former consists of a number of short In the article by Dr. Hare, Mr. Moses inelastic hollow rods fitting loosely one

Shaw, of Nova Scotia, is mentioned as hav. into the other, and connected by a rope

ing first suggested the idea of igniting the passing through the whole.

Never em

powder in blasting rocks, by the aid of the

electric fluid. ploy any person who uses this machine.

That gentleman had purGlass's machine-which is sanctioned

sued the subject with much persevering inby parliament, and is the machine by

dustry, contending, at the same time, against which the perfect and efficient sweeping

pecuniary difficulties, and a want of those

resources which science alone can supply, in of chimneys by mechanical means was

the prosecution of such undertakings. He completely established-consists of

well merits, however, to have his name as. number of elastic bamboos firmly con sociated with those who have brought the nected together by screwed feruie joints.* matter to a successful issue.-EDITOR. This machine is sufficiently pliable to sweep all ordinary chimneys, and with a Dear Sir,-Knowing the great interest you little contrivance, every chimney in ex have always manifested in all engineering istence; while its firmness and stability operations connected with the construction enable the user to cleanse the chimney of public works, it affords me pleasure to more effectually than boys have ever communicate to you an account of the transdone.

actions within the past summer at this NavyGlass's, at present, is the only machine yard, in blasting rocks under water by means

of the galvanic battery. that can be depended upon; when chim

The application of this means to purposes neys require sweeping, therefore, see that

of blasting is somewhat novel, as you are this machine is employed : it differs so

well aware, and the account of Colonel greatly from the other that there can be

Pasley's experiments in England has given no mistake, and housekeepers may de

to the public the first notice of its being thus pend upon it, that those parties who will employed. Since the blowing up of the still continue to use the old inefficient

wreck of the Royal George, it has been suc. machines, only do so for the purpose of cessfully used in England in blasting rocks causing annoyance and bringing mecha and clearing harbours, rivers, &c, from ob. nical chimney sweeping into disrepute, structions: it bids fair to entirely supersede by showing how very badly chimneys the old methods of blasting, both in civil and can be swept by a bad machine, worked military operations, especially in the latter, in the worst possible manner.

where it becomes a tremendous agent for the instantaneous explosion of mines, &c.

a

• Described with illustrated engravings, at page 184 of vol. ix.

• September, 1833.

BLASTING ROCKS UNDER WATER BY GALVANIC IGNITION.

69

In the detailed accounts of the experi paring the bottom for the reception of the ments tried by Col. Pasley, it appears that foundation of the walls, I was greatly at at first many difficulties were encountered ; loss which to adopt. It appeared to me, and the numerous failures seemed to forbid that in adopting the method practised by any hope of success in large operations, Col. Pasley, great expense and difficulty although the result of those on a smaller would be incurred ; and as it did not appear scale generally proved satisfactory. Perse that this method had been employed in blastverance, however, enabled the operators, ing the solid rock at the bottom of a river, after many trials, to render the explosion of in any of his experiments, I was somewhat the charge under water as certain as by the apprehensive of its utility for operations of ordinary methods on dry land; and the sub this kind, and whether the cost would justify sequent success in blowing up sunken wrecks, the trial. In order to satisfy myself with re&c., at the bottom of the Medway river, and gard to the expense of an experiment with at Spithead, proved the utility of the means, the galvanic battery, I applied to Mr. Daniel and amply compensated for the labour and Davies, junior, philosophical instrument expense incurred in the first attempts. maker, of Boston, for the necessary informa

Our operations during the past season tion, when I was convinced that a very were confined chiefly to the construction of trifling expense would procure such a trial quay walls and the foundations of two launch as would satisfactorily decide the merits of ing ways, the whole of which were built of the apparatus. Mr. Davis kindly assisted stone. The character of the bottom of the me in making the experiments which were river where the work was laid rendered tried at the Navy-yard at Charlestown, and blasting or other means necessary, before a I had the pleasure of witnessing the most proper surface for the foundation could be

satisfactory results, and without hesitation obtained; it was desirable to give it a slight determined to apply the means to the work inclination inwards, so that the face of each in hand. course of stone should lie somewhat higher The galvanic battery, which was conthan the inside, thus preserving a proper structed by Mr. Davis, was one of Dr. Hare's batter of the walls, and rendering them per invention, of Philadelphia. It consists of fectly secure. This bottom is a hard slate two vessels or jars, each formed by two conrock, and, with the exception of some level centric cylinders of copper, admitting of a portions, extremely uneven, with slopes of cylinder of zinc between. Two copper wires, almost every grade, generally in an outward termed the conducting wires, formed the direction from the shore. The depth of medium by which the electrical fluid was water in the line of the walls varies from communicated to the charge from the batfifteen to twenty feet at low water, and from tery. These wires were closely wound with twenty-five to thirty below the high tides. thread, in order to prevent their coming in This depth of water, added to a strong and contact with each other, and both tightly variable current, caused me to anticipate covered with tape, and afterwards served much difficulty and great expense in all ope round with twine, thus forming a single coil. rations below its surface.

At each extremity of the coil the wires were But we were, fortunately, provided with a separated for a few inches, like a fork. This fine diving apparatus, consisting of a cast form of the galvanic battery, termed by Dr. iron diving-bell, and a powerful air-pump Hare, the “ Calorimoter,” is the most simple attached. This apparatus was worked from and portable of any that I have seen; its a vessel of strong construction and light power for blasting gunpowder may be indraught, fitted expressly for the purpose. A creased to any required degree, either by ensystem of signals and messengers was esta larging the size of the jars, or increasing blished for communication between the work. their number. We had, in addition to this men in the bell and those on board the ves apparatus, a simple contrivance for proving sel ; by these means every want was speedily the charges of powder, which is termed the made known and answered. Four workmen, “ Electrometer.” divided in two gangs, were employed for The charges used in blasting consisted of working in the bell, which made four descents various quantities of gunpowder, according per day, occupying at each time two and a to the effect required, from four ounces to a half hours, the two gangs alternately relieving pound. They were enclosed in perfectly aireach other. The bell was amply supplied tight tin cannisters, the smallest being an with a constant stream of fresh air, and but inch and a quarter in diameter, and the diatwo or three inches of water remained in it meter of the largest about two inches; the at its greatest depth, so that the men worked lengths of the cannisters were eight or nine in a comfortable state, perfectly dry, and inches. Two copper wires were introduced with no more difficulty of respiration than into the cannister, about half-way down, on dry land.

with the extremities connected by a fine plaIn deciding upon the best means for pre tinum wire; the other ends of the wires pro

jected twenty or twenty-five inches beyond is great expense and trouble saved in the the mouth of the cannister, which, after absence of the train or fuse, which was inbeing filled with powder, was closed, and ef dispensable in the old methods, especially fectually secured with a water-proof compo

under water, where was always required a sition. It will be observed, in thus prepar water-tight hose or tube leading to the suring the charges, that the whole is completely face, which was always destroyed by the exair and water tight, and that no vent to the plosion. Here nothing is lost or injured, powder remains, an advantage of which I except the cannister containing the charge. shall further speak.

The explosion of the charge is reduced almost The operation of blasting is carried on in to certainty, and should cases of failure octhe following manner. The hole in the rock

cur,

it can be approached with safety, with. for the reception of the charge is drilled to a out the suspicion that fire may be near it. proper depth by the workmen in the bell; The most important advantage, in an ecothe cannister is then inserted, with the ends nomical view, is, that the effect of the charges of the copper wires extending outside of the is much greater than in the old way, in conhole, which is then filled up or tamped with sequence of there being no vent-hole; the coarse sand. The ends of the conducting whole explosive force of the powder is thus wires are then connected, by means of gained, while by the old methods much of it clamps, to the wires leading from the

is lost. Our smallest charges displaced a charge; the other end of the coil is then led much greater quantity of rock than the same up, as the bell is hoisted to the surface, to amount of powder by the old means, which the battery, which, in all our experiments, we had opportunities of experiencing. With was placed on a floating stage directly over these advantages, this method of blasting the charge. The jars forming the battery

places in our hands the most ample means are brought near each other, and their whole of clearing harbours and rivers of rocks, &c. power concentrated by connecting them to in any reasonable depth of water. gether with a short copper wire; the end of

In using Dr. Hare's apparatus, it apone of the conducting wires is then brought peared that an important advantage was in contact with one pole of the battery, and gained over that of Professor Daniell's, emthe end of the remaining wire similarly dis ployed by Col. Pasley, inasmuch as a very posed with the other pole, when the explo troublesome arrangement, indispensable in sion instantly follows, by the platinum wire the latter, was avoided. This consisted in in the charge becoming intensely heated as not being obliged to insulate the conducting the electrical current passes through the

wires from the water, as in such a case the conducting wires.

connexion of the conducting wires with the We made during the past season nine

charge must be made before the cannisters blasts, with but one failure, which was caused are placed in the rock; every portion, then, by the platinum wire in the charge becoming

of the wires where the connexion is made accidentally broken, so as to render the

must be covered with the waterproof comelectrical circle incomplete; this probably

position. By Professor Daniell's apparatus, occurred in tamping, an operation which

it appeared that water was a conductor, thus must be conducted with care, as this acci destroying the electrical circle, if any part of dent is most liable to be incurred, of all

the conducting wires came in contact with it. others, owing to the extreme delicacy of the

Though Dr. Hare's battery was known to wire. The object of the electrometer is to

Col. Pasley, it was not adopted in his expedetect whether this has taken place before

riments, the reason assigned being that "it the charge is inserted in the rock, and may

did not appear that he had ever used it under always be ascertained by a simple trial.

water." It must be obvious to every one, at all

I have the honour, Sir, to be,

Your obedient servant, experienced in blasting rocks, that this method has advantages, in many respects, over

ALEXANDER Paris, C.E.

Col. S. Thayer, Boston. the old methods, both under and out of

Navy-yard, Portsmouth, N. H., Nov. 9, 1810. water. The danger of accidental explosions is entirely prevented; these occur, for the most part, in the old practice, by careless

BRIGHTON ness, while in this, great care and nicety are required to produce the explosion. There is We lately inserted a description of very little time required in charging, as the Captain Tayler's Floating Breakwater, cannister is simply inserted in the hole, and as proposed to be applied at Brighton, tamped with sand; the whole time occupied (No. 952, for November, 18+1). We in this operation, and making the connexion have been since favoured with a copy with the conducting wires, in the present of an Address by our esteemed correcases, rarely exceeded twenty minutes. There

spondent, Mr. G. A. Wigney, to his

BREAKWATER AND

OF REFUGE.

HARBOUR

a

BRIGHTON BREAKWATER AND HARBOUR OF REFUGE.

71 "Fellow Townsmen,” in which he lays therefore admissible to vessels of the greatest before then the plan of a solid break

burthen. The southern breakwater will furwater, of a peculiar construction, which nish a light-house in the centre, 100 feet in he has invented, and the adoption of height, or 55 in height above the highest which he advocates with his usual ability,

spring tides. The eastern and western 18 offering many advantages which no

towers of such breakwater, and the southern

towers of the eastern and western breakfloating breakwater can ever possess. Mr. Wigney, referring to Public

waters, will furnish lights to direct vessels

to each entrance. Meeting held at Brighton to consider of

As a Protective Harbour, it will furCaptain Tayler's plan, thus explains the

nish, from the entrance to the interior, water circumstances which led to the origina- gradually diminishing from the turbulence of tion of his own.

the tempest to the stillness of a calm ; and ** Subsequent to the meeting, and in the

the addition of an inner breakwater may at afternoon of the same day, I was informed

any time be made, to increase the security by a person of the substance of what had

of the shipping within, should such a mea

sure ever be deemed necessary. At the transpired, accompanied with the observation :- How much better it would be to

highest spring tides, each tower will present bare a solid breakwater.' In reply to such

a barrier to the waves fifteen feet in height observation, I stated that, being without a

above the level of the sea, and the intersupply of stone in the neighbourhood, the

mediate caissons a rampart of ten feet. construction of a solid breakwater was out

As a Fortified Harbour, and an Armed of the question, and that in those places

Line of Defence for the Town in time of where an abundant supply could be com

War, I conceive that this structure is ad. manded, the enormous cost of construction

mirably adapted ; as each tower, with the was almost an insuperable barrier to its ac

light-house, being mounted with one gun,

will furnish a southern crescent battery of complishment. But while conversing on the subject, it occurred to me, that the formation

thirty-seven guns, and an eastern and westof one with cast-iron plates, filled with con

ern battery of eighteen guns each, which crete, was not only practicable, but that its

may be of sufficient reach to cover the whole cost of construction, and superior adaptation

town from east to west; affording not only

a certain and instantaneous protection to the for the purpose, rendered it a subject well worth consideration and inquiry; and having

shipping within its precincts, and to the communicated the idea to the person with

magnificent property which so splendidly

adorns the sea-girt borders of your town, whom I was talking, I left with a determination to pursue the subject yet further."

but also a safe and peaceful residence and resort, in time of war, to those residents and

visitors whose support is indispensably neMr. Wigoey then mentions other cir

cessary to your welfare and prosperity. cumstances connected with the matur

“ As a Panoramic Exhibition of Marine ing of his plan, and thus proceeds to de

Scenery, the imagination alone can furnish scribe it more in detail.

data for a description of the reality. Vessels * As a Structure, it will be composed of, of war, steam-packets, regatta yachts, ships (comparatively speaking,) indestructible ma of merchandise, boats for fishing, and skiff's terials of cast-iron plates, coated with gas for pleasure, will constitute the pleasing tar, well united by bolts, and rendered im group that must delight the eye of every pervious to water; capable of replacement, gazer. if ever worn out, and filled with concrete in " As a Protective Girdle to the Chain creasing annually in durability, of such an Pier, which beautiful structure is shown in enormous weight, as will render its stability its centre, the security which it will furnish secure, I conceive, against the most violent will be effective and complete, and the emstorms, and to which an indubitable security barkation from its platform at all times safe may be added by piles and moorings, should and pleasant. any doubt prevail as to its safety without. “As an additional and more extensive And to prevent the possibility of any accu Promenade than is now furnished by the mulation of sand, gravel, or other obstruc Chain Pier, the iron ramparts on the eastern tion, either to the entrance or elsewhere, the and the western side will present a conarched caissons allowing a clear run of ten tinuous road-way, 12 feet in width, and feet of water beneath will obviate every such nearly 3,000 feet in length ; and at the end liability.

of each, a flight of steps will enable the pe" As a Harbour of Refuge, it furnishes destrian to pass, by boat or floating-bridge, an entrance from the east, and another from the harbour's mouth; and ascending the the west, of requisite breadth, with twenty. southern breakwater, he may extend his six feet depth of water at low tide, and walk a further distance of above 3,000 feet,

*

*

and making his return by the opposite tates of prudence naturally prompt the sugcourse to that on which he commenced his gestion, that in case it should be deemed tour, he will, on reaching the shore, have desirable by my fellow-townsmen that so imenjoyed all the exquisite pleasures attendant portant and great an undertaking should be on the circuit of about 10,000 feet in dis accomplished, that in the first instance a tance.

sufficient number of eminent engineers and As a Mercantile Harbour, although we competent nautical judges should be conhappily do not at present need one, and its sulted as to the probability of the realization appropriation for the purpose might be in of the anticipated advantages, and the pracjurious to the welfare of the town, and prove ticability of carrying the work into effect; inimical to the interests of the proprietors of and to facilitate such inquiry, I beg to refer Shoreham harbour and the Railway Company, you to the perspective drawing and model which (for one) I consider we are in justice which I have caused to be made, and which bound not to oppose, but on the contrary to may be publicly seen at the Town Hall. support; yet should any fortuitous circum Should their report be favourable, I beg to stances ever require its use for such a pur submit the suggestion that a subscription pose, it will at all times be a source of plea should be endeavoured to be raised for the sure to reflect that you have the means of purpose of providing and placing in their availing yourself of its resources for the pur designed situations the lighthouse of the pose, and having devised means for the trans southern breakwater, the two adjoining mission of the merchandise unshipped to one towers, and the two intermediate caissons, or more unobjectionable situations without as shown by the model, in the following interfering with the marine drive, the great spring and summer, and allow the succeeding est objection to its use as a mercantile har. winter to pass over in order to test the prinbour may thereby be obviated ; and I beg ciple fairly, to ascertain if any improvement leave to take the liberty to suggest, that in can be made in the principle or mode of justice to the Chain Pier Company, the use construction, and to furnish the requisite of the breakwaters as a promenade should be experience which it may be desirable to oba subject of pecuniary arrangement with them, tain, preparatory to the execution of the and which, I conceive, it would be to the in work to the extent of completion. terest of both parties to endeavour to effect. “ To ascertain the necessary amount to

As a Protective Harbour to Fishermen, perform this experimental portion of the the cause of humanity, the welfare of a class work, there are the same difficulties in the so numerous and interesting, and the pecu way as have occurred in making out the estiniary interests of the rate-payers are power

mate for the whole; and as the execution of ful inducements to provide them a haven so this minor portion will require nearly all beneficial in the hour of danger, so stimula those erections and subsidiary expenses as tive to habits of industry, from a conscious would be necessary to accomplish the whole, ness on their parts of being able to pursue so therefore must the estimate for such portheir calling in dangerous (yet for their pur tion much exceed the proportionate amount pose the most propitious) weather, having a that would be incurred by its execution with port of refuge to fly to, from the eastern, the rest. But as such erections will serve western, and southern quarters, in every case their required purpose in ultimately comof imminent peril.

pleting the work, such an outlay will not be “ Having enumerated, I trust, a sufficient finally lost, provided it is deemed desirable amount of advantages to stimulate you to the to finish it. The amount requisite to carry endeavour to obtain them, I hope I shall into effect this experimental test, I have stand excused from entering into a detail of reason to believe will not exceed 70001. ; many others that reveal themselves in pros but I should suggest that 80001., in 51. pective, and for passing on to

shares, be raised, and that such shares should The Estimate, which, with the able as become available, in case it should ultimately sistance of several competent persons I have be deemed desirable to form a company for been able to arrive at the amount, as well as the completion of the work, of which the the insufficiency of data on a work of so original shareholders would form the nucleus. novel and peculiar a character will admit; The Execution of the Work. That in and having made an ample allowance for con the accomplishment of a work of such magtingencies, I feel warranted in stating that, I nitude and novelty, many unforeseen diffithink, the amount will be considerably under culties may occur in addition to those which 200,0001., one-third of which will be payable have been already anticipated and mentally for manual labour, a circumstance very far provided for, there can be but little doubt; from being nportant to all those who are but let them be what ney may, I feel as. interested in the employment of the labour sured that in the present day, abounding with ing classes.

so many stupendous and successfully exe" The Testing of the Principle.—The dic. cuted projects, that sufficient engineering

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