THE NEW- YORK EXHIBITION ILLUSTRATED.

Portance, must take the lead alike in commerce as it does in the arts, and apartfrom the ripening influence of the latter, must realize advantages ot no mean im-

ELEOTRIO TELEGRAPHS.

A MONG the many applications of electricity to the arts and requirements ofcivilised life, there is none which plays so admirable and so impoitan a pas the Electric Telegraph. Its power is a perpetual miracle, and its consequences,Political and social, .might be the theme of the grandest prophecy. It is one°f those immortal discoveries that give character to an age, and wou n . eown for ever memorable, though it stood alone, the solitaiy achievemetime. The capabilities of the Electric Telegraph have already far exceeded thehopes of the most sanguine of its early friends, and what it now pi °P° ’

without a knowledge of its past history, would be pronounced mos ^ ex 1and chimerical. It no longer confines its operations to mdividua ooun 11and continents, but is stretching its bonds of intelligence and amity acrossthe wastes of oceans, and preparing to make every man a bl0S T el °’ mfar swifter and more accomplished Ariel to serve him. Oui an 10 sbring us intelligence from all parts of Europe up to the momendeparture, by means of the electric link, which, lying deep m the aim othe ocean between England and France, silently conveys the news ,

Intions upon which hang the fate of nations. A company ias eento connect Cuba with Florida, and another has failly enteie upon .of spanning the Atlantic. How that it is the most prominent i nt.ficapplication of the age, old inventions and ideas, which, at t e ime °ception, had only vitality enough to find a place in the lecoi o 1 ’ ‘

had since slumbered for years, have again come to life, and deriving s gimportance from tlieir antagonists, have urged a competition oi lono , 1]t

inventions which first converted an abstract idea into a piac ica. ac , ^ TPr-iiicis

it forward for the benefit of the world. In the first expenmeiffs Ml™

Ronalds, of England, who proposed and built, in 18 ^’“ enclosed

distance of 175 yards, operated by frictional electricity, the \ ,

in thick glass tubes carefully joined with wax, and placed uiidergiountroughs lined and covered with pitch; and it is now a well f abllshed 1fact [PM. Trans., vol. XIV., 1848], that more than one hundred yea. agHli. ALd

son extended his experiments over a space of two miles neai Lon > ^

single wire, the ground forming the return and comp e mg i current

in the year 1748, Dr. Franklin_set fire to spirits by ~ of an elec^hwuu..cut

sent across the Schuylkill on a wire, and returning * e con a„ c ti„g

the earth. In 1837 it was again discoveied by b f w : res an( j

power of the earth could be advantageously substituted for onthat it was unnecessary to connect each pole ofthe battery with the telegraph apparatus at thedistant station. The saving of the cost andrepairs of one out of every two wires is notthe only advantage'derived from this discovery.

The conducting power of the earth is so supe-rior, that it adds nothing to the resistance, andacts too as the return connection to an} T num-ber of distinct wires and batteries, withoutaffecting the independent action of any ofthem. It is believed that in the year 1825-Mr. Sturgeon, of England, constructed thefirst electro-magnet , by coiling a copper wirearound a piece of iron of a horse-shoe form,tie turns being kept apart to prevent thetransmission of the electricity between them.

He found that when the electricity was passingthrough the coil, the inert mass of iron enclosedw as endowed with all the wonderful properties°fa magnet, and lost them again on the instant

the current was interrupted. , . ,.

But it is not our intention to write a history of the ideas an ( is -'which reached their consummation in the Electric Telegiapli. ® ia 7t° explain the methods mostly in use upon the fifteen thousand mi es o -e eg Pfines now in operation in the United States, and which are l us ia e( y

porcelain cup. In the glass cups, which contain sulphuric acid diluted withwater, are immersed cylindrical pieces of zinc, connected witli slips of platina foilwhich dip into the diluted nitric acid filling the porcelain enp in the adjoining

portance to its future progress in civilisation.

We have devoted so considerable a space of the Record to the history of the j tumbler. The decomposition of the zinc is rendered less rapid by amalgamationfoundation and vicissitudes of the schools of Ornamental Art in England, and to ’

an explanation of the course of study pursued in them, not only because wethought the subject a highly important one, but in the hope that our article mightattract attention here, and induce wealthy, influential, and liberal citizens to pro-vide similar schools for the instruction of our own artisans.

or coating it witli mercury rubbed into its surface. The platina at one end of t.hcrow or series, or its wire connection, is called the positive pole, and the zinc atthe other is the negative pole. The circuit is closed,- and the current establishedby connecting the wires or terminating them in tlio^arth; and it may includeany number of machines for telegraphic purposes. The chief difficulty experi-enced is to keep the wires unbroken and to avoid the disturbing action of at-mospheric electricity and the destructive effect of lightning. The wires in thiscountry are hung from glass or porcelain insulators on poles, and in some parts ofEurope they are incased in gutta percha and buried in the ground. Variouscombinations of telegraph wires insulated with gutta percha, and protectedwith wire rope and vertebrated iron chains, have been used in crossing riversand the sea.

Almost every effect by which the presence of electricity is manifested, 1msbeen enlisted for the purpose of transmitting ideas to a distance. Tho electro-chemical telegraph of Bain records by means of the decomposing power ofelectricity. It consists of an iron point connecting with the positive pole of thobattery, and quietly resting upon a circular brass disc, with which it forms part ofthe circuit. If paper moistened with a solution of prussiate of potash, slightlyacidulated with nitric or sulphuric acid, is placed between tho point and disc, anda current of electricity passed through, an oxydation of the iron and combinationwith the prussiate is induced, forming prussian blue and depositing a dark bluemark. The disc is revolved by clock-work, and the iron point is guided by anarm resting in a groove in the central portion of the plate, and traces dots andmarks or blanks in a spiral direction on the paper as the current is closed orbroken. The discoloration is effected instantaneously, and it has the additionaladvantage of being performed with a much more feeble current of electricity thanwould bo required to produce a' mechanical result. Thoro have been several mod-ifications proposed for the purpose of transmitting foe-simile copies. The princi-ple involved is to break and close the current by writing with dissolved sealingwax or other non-conducting material on the surface of a cylinder included inthe circuit. Tho cylinder revolves slowly by means of clock-work, and as thefine point of the style passes over the writing, the current is broken, and there isa blank left on the prepared paper wrapped upon a similarly conditioned cylin-der at the other terminus, which the electricity would otherwise cover with afinely traced helix. The axes of the cylinders aro out with screw threads, so thata revolution shifts them endways a slight distance, corresponding to tho finenessof the screw. When this machine becomes a quick-working and reliable instru-ment, it will bo an important acquisition in business operations, and might hefound useful in transmitting an outline picture or likeness of a fugitive rogue.

Tlie first application for a patent for an electric telegraph, by Samuel E. B.

Morse, was made in 1837; and thefirst line in the United States wasU- built by him, in 1844, between Wash-

ington and Baltimore, in which enter-prise lie was assisted with thirty

aes now in operation in theWorking machines exhibited in the Crystal Palace. .

Grove’s batteries are most generally used in ,

Urove’s batteries are most generally usea in , „ T , 0 .i n7P j

series of glass cups or ordinary tumblers, in each of which is plac g

morse's electromagnetic telegraph.

thousand dollars, appropriated for the purpose by Congress. In tlie recordinginstrument represented above, there is a pieco of pure, soft iron, of theordinary horse-shoe magnet form, wrapped with many hundred convolutions of finecopper wire carefully insulated by a covering of silk. When the circuit is closed,and the current of electricity flows through the wire, the iron becomes magnet-ized, awl attracts the armatures attached to ono of tho arms of an axis, which car-ries on its opposite side an arm furnished with a steel point, regulated by a screw,

and consist of a

and pressing through the interposed papor^into a groove cut on one of the rollers