In treating 0: 
bject, researches in which, had presented t Ps 
ilages to civilized life, iularly as to rapid means 
ommunication and its resus e should have to'consider it me~ 
different heads:—1. Those telegraphs which were worke 
or frictional electricity——2. Those employing a current of saad 
from a volt attery.—3. se which are worked by electro- -mag- 
netism, induced by a voltaic batter ry. “4. ha operated on by mag- 
neto-electricity.—Dr. Ryan then rh to the process of obtaining 
a current of frictional electricity, by rubbi —— shellac, sealing-wax, 
, so well known as to require no repe ito e then went into some 
étatistical data, as to ot progress of electric aqhoggen pb In 1744, the 
arin mployed this electricity in striking bells ; in 1746, Granarth 
mtibok to twenty persons-at a great dist tance; Winkler and Mo- 
nin oe te a current through 4000 feet of wire, the water in the basin 
of the Sulla forming ves circuit; in 1746, the celebrated 
Dr. Watso n passed a current ugh. miles of wire, water form- 
ing half the circuit, and he observed ho time appeared to elapse 
during th the passage of the shock. In 1787, Lomonde, in France, 
constructed a élegraph, by the aid of,an electroscope at the end of the 
conductor, to be communicated with ita which two pith-balls covered 
h-of the letters of the alphabet. * On,completing the circuit at one 
end with any particular letter, the pith-balls were repelled, and open- 
ing, asunder, showed a similar letter at the other end, and thus gave a 
means of communication; and, in 1793, the higstraity: or ae x 
on tin-foil letters, was proposed for tele raphie purposes. In 1 r ll 
Salva, in Spain, construeted ah electric: telegraph, between Madrid. and 
Aranjuez, twenty-six miles, which must, at that time, have been a great 
and bold undertaking. The lecturer‘came now to age ar 1800, which | 
he described as a most important périod, as it d the investiga 
tions and correspondence between Galvani and Vol which developed 
the properties of electricity from a metallic battery, and has immortal- 
ized their names. ‘The difference between frictional and galvanic or 
voltaic electricity, was one of the most int@resting considerations in nat- 
te phi ilosophy. In 1803, Bassi passed a current of voltai¢ electricity 
through 4000 feet of water; in 1809, Scemmering constructed a tele- 
graph on Ay jaaveioieg of the powers of voltaic currents in decomposing 
water; he tic 
d represei the several letters of the alphabet, or conven 
tional 3 and on-completing the circu it, the water immedia' 
sinking in any tube, showed the letter, or sign, communicated, which 
was easily and quickly read off. In 1803, Ronalds, of Hammersmith, 
pence a telegraph by galvanism, through coils of eight miles of 
, a description of which he published at the time.t In 1817, the ) 
iatatieared Wedgewood also formed a voltaic telegraph; but no descrip- 
Ph EOE Ie 
a ‘Here should also have been seitaea the attempts of Lesage i in 1774, who made 
a telegraphic instrument, consisting of twenty-four insulated — RE at 
ne end in p phepall electroscope. (See Enc cyc. Amer. Sup.)— 
[ r. Coxe passed signals along a wire a mile long, saad, around 
‘his lecture room at the University of Pennsylvania, and perpved to use it as a 
telegraph, by icing chemical changes on prepared ‘pa is 
pulled in 1816, in Thomson’s Annals of Philosophy. id—Eps 
