EXPERIMENTS ON THE ELECTRIC PILE. 173 



This, of which I at one time defpaired, may be attained by A veffd of ice 

 the Ample contrivance of employing a veflel of ice! If a l^wMnz^ri* 

 cylindrical veflel of ice be procured fimilar to that ufed in the will notraifethe 

 preceding experiments, and if a thermometer be fixed in it, t f™ P fl r *j U 'i e • 

 if on filling it with a fluid at the temperature of 32°, and j ts own fufion. 

 lufpending in it, at a fhort diflance from the bulb of the ther- 

 mometer, a heated folid, any rife of temperature take place, 

 it may be considered as a certain proof of a conducting power 

 in the fluid. No caloric could poflibly be conveyed to it by 

 means of the veflel, fince ice cannot have its temperature 

 above 32^, and there is no other mode by which the caloric 

 can pafs from the ball to the thermometer than by the inter- 

 poled fluid. Of the experiments made to determine this 

 point, an account will be given in a fubfequent memoir. 



III. 



Letter from Dr. Van Marum to Mr. Volta, Profejfor at 

 Paiia, containing Experiments on the Eletiric Pile, made by 

 him and Profejfor Pf a ff, in the Teylerian Laboratory at 

 Haarlem, in November, 1801.* 



•JL HE weather and feafon of the year preventing thefe gen- Van Marum's 



tlemen from attempting to charge the whole of the great experiments on 

 TT JZ. n • \ ■ ii the galvanic pile. 



Haarlem battery, confi fling of 100 jars, in general nearly* a 



line thick, and containing five fquare feet and a half of coat- 

 ing each, with the galvanic pile, they took five-and- twenty 

 of thefe jars, which they charged feparately, a few at a time, 

 and all together; and uniformly found the Angle jars or the 

 batteries charged to the fame degree of intenflty as the pile. 

 They had taken twenty-fix jars, but one of them did not 

 receive the charge well, which they afcribe to the too great 

 thicknefs of the glafs. 



They next charged the battery of 137| fquare (eet with a Battery of 137! 

 greater or lefs portion of the pile, by foldering a hook to ^ uare , le b et - t f 

 every twentieth plate of zinc, to which the infulated metallic 

 wire for producing the communication between the battery 

 and the pile might be conveniently attached. Beginning at 



• Abridged from the Annales de Chimie, No, 120, Vol, XL. 

 p. 289.— C. 



the 



