SfiCT.VII.] Optics, G7 



above mentioned, discoveries and improvements 

 relative to microscopes, too numerous to be re- 

 counted, have been made by philosophers and 

 practical opticians. The most conspicuous of these 

 are Culpeppei-j Baker, Ellis, Lyonet, Martin, CufT, 

 Adams, and Withering 5 who have either contrived 

 microscopes suitable for particular purposes, or 

 suggested inventions and additions of more general 

 application. 



There is probably no division of this review, 

 under which another modern invention, the Ttlt- 

 graphy may with more propriety be placed than 

 this. Though something like Telegraphic com- 

 munications had been attempted many centuries 

 before, on particular military or civil emergencies ^ 

 yet nothing of this kind was reduced to regular 

 system, or much known, till the beginning of the 

 eighteenth century*, when M. Amontons, of 

 France, exhibited a telegraph on a new and con- 

 venient plan. It was not^ however, until after the 

 commencement of the French revolution that this 

 machine was generally applied to useful purposes, 

 or became an object of much attention. Toward 

 the end of the year 1793 M. Chappe announced 

 an invention under this name. Whether he were 

 acquainted wdth the contrivance of M. Amontons 

 is not known ^ but be this as it may, his was 

 nearly on the same plan. Tlie invention of M. 



* It is said by a writer in the Philosophical Magazine of Lon- 

 don, that the celebrated Robert Hooke, the contemporar>- and 

 friend of Boyle, invented a Ttltgraph, on the same gt;iicral plan 

 as those which have been since used ; and formally arjiounced 

 and described it, m a paper read beiurc tlie Koyal Scc:^'. 

 May 21st, 1684. 



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