22£ 



Increased the 

 power of the 

 cylinder. 



Plate machine. 



Cylinder. 



lime's electro- 

 meter not to be 

 depended on. 



COMPAftATIVE POWERS OE ELECTRlCAt MACHINES. 



deranged it, as to render a comparison with the new plate 

 machine unfair. The result answered my most sanguine 

 expectation. The rubber and its new silk being completed* 

 I found the power of the cylhder machine increased one 

 third; for a trial ar, which had before exploded four times 

 in one turn of the wheel, now afforded six explosions in one 

 turn. The experiment was several times repeated, and the 

 result was uniformly the same. 



The following comparative experiments were then made: 



Exp. 1. Length of spark, from th« prime conductor of 

 the plate machine, to a two inch ball connected with the 

 ground. The greatest interval, obtained by gradually in- 

 creasing the distance between the balls, till the limit at 

 which the spark would pass was ascertained, six inches and 

 a half. 



Exp. 2. The same arrangement with the cylinder. The 

 greatest striking distance eight inches and a half. With 

 larger balls, a longer spark could be obtained; I have oc« 

 casionally procured them upwards of 12 inches; but it is 

 requisite for this purpose to turn the machine very slowly^ 

 which occasions undulation. 



Experiments were next made on the charge of a jar fitted 

 up with Lane's electrometer. The following table exhibits 

 the most uniform results obtained in a great number of ex«* 

 periments; and may show how little reliance is to be placed 

 on the accuracy of this test. 



Jar of KS8 square inches. 



Cuthbertson's The anomalies in the experiments with Lane's electrons 

 electrometer. ter are not more remai kable than the uniform accuracy o 



the following, which were made with Mr. Cuthbertson's 



most excellent electrometer. 



Jaf 



