150 



in the same 

 manner. 



The camera 

 lucida 

 superior to 

 everj other 

 contrivance. 



BEST CONSTRUCTION OF A VOLTAIC APPARATUS. 



horizontal position cf the eye hole, by bringing the micro- 

 scope to the same position, and the face of the prism close 

 to its first eye glass. A telescope may likewise be employ- 

 ed ; having previously removed the head or cover, the face 

 of the prism must be brought into contact with the eye 

 glass, to which it serves as a diagonal eye piece: a distant 

 object is the:> approximated, appears reflected upon the pa- 

 per as before, and may be delineated in a manner at once 

 pleasing, novel, antj correct 



Ttie'se combined advantages, and above all, the truth of 

 the reflected image under every circumstance, give the ca~ 

 mera lucida a decided superiority over all other known con- 

 trivances for the same purpose. And if the hints I have of- 

 fered should enable Mr. Sheldrake, or any of your readers, 

 to derive farther gratification in the use of the instrument 

 than they have hitherto received, or call to notice any un- 

 expected purpose, T o which it may be applied, I shall be 

 nappy in having contributed, however poorly, to that gra- 

 tification. 



I am, Sir, 



Poultry, Uth Sept. 1S0Q. 



Your very obedient servant, 

 K. B. BATE. 



X. 



An Account bf sow? Experiments, performed with a View to 

 ascertain the most advantageous Method of constructing a 

 Voltaic Apparatus, for the Purposes of Chemical Research, 

 J3y John George Children, Esq. F. R.S*. 



c ' A. HE late interesting discoveries by Mr. Davy having 

 shown the high importance of the voltaic battery, as an in- 

 strument of chemical analysis, it became a desirable object 

 to ascertain that mode of constructing it, by which the 

 greatest effect may be produced, with the least waste of 

 power and expense. 

 jS,utery after For this purpose, I made a battery, on the new method, 



BeRt eonstrn 



tion <>f;i voltaic 

 battery desi 

 We. 



* PhilosJ 7 ransact. for 1809, p. 02. 



ith 



