Q36 NEW CLASSES OF GALVANIC CONDUCTORS, 



all the changes, that characterise each state of the pile. In 

 the nice experiments I have to relate, it will be seen, that 

 the number of simultaneous observations to be made would 

 render the use of the condenser extremely inconvenient : 

 and if the modifications necessarily produced at each pole 

 by the augmentation of the electric capacity, that results 

 from the very application of the condenser, be considered. 

 The gold leaf the reason of my excluding it will be obvious. Gold leaf 

 very conveni- electrometers, applied immediately to the poles, and to the 

 e«it. the subjects of the experiments, are free from every incon- 



venience; and if they be ever so little sensible, they indicate 

 with extreme fidelity and promptness the progress and de- 

 gree of the most complicated modifications, that the pile un- 

 dergoes. 

 The apparatus Another essential condition to the success of the investi- 

 fectly insulat'- g at i° n iS > tnat t^ e pile an & *&\ parts of the apparatus be per- 

 ed. fectly insulated. I have found no mode of insulating the pile 



better than to fix it in the centre of a large cake of resin, 

 taking care not to render the cake an electrophorus by any 

 Glass not suffi- accidental friction. As to the other parts of the apparatus, 

 we should never trust to the insulating power of glass alone; 

 and in applying a resinous coating to the surfaces, 1 have 

 found the dry way far preferable to the moist. Lastly, be- 

 fore commencing the experiments, and during their course, 

 it is proper to try by means that may readily be contrived 

 and varied, whether all parts of the apparatus completely 

 Particular at- insulate the electric effects : and it is particularly impor- 

 tention to the tant, to pay this attention to the electrometers, to be certain 

 ^ e e c ° e t s ro ™ eter whether the glass of these instruments, which cannot be 

 coated with resin, preserve itself constantly in a perfectly in- 

 sulating state. I know by experience, that the progress of 

 the observations is frequently confused, from the surface of 

 the electrometer having imperceptibly become a conductor. 

 This inconvenience is remedied by drying the instrument, 

 and not by exhausting it, for fear of falling into a still worse 

 inconvenience, the communicating to the glass an electric 

 charge. 



Sect. 



