240 Silk Manufacture. 



a nature as to communicate but little electricity to glass, the ex- 

 citement did not depend upon the action of the rubber, but upon 

 the body whereon it was placed. In such a case, the black silk 

 was always resinously and the white vitreously affected. But if 

 the ribin was of a close unyielding texture, and the nature of 

 the rubber such as would communicate a high degree of electrici- 

 ty to glass, then the excitement of the upper piece depended al- 

 together upon the rubber. Thus, if a white silk stocking were 

 rubbed with gilt paper upon glass, it became resinously and the 

 glass vitreously electrified; but if the piece of silk thus placed upon 

 the plate of glass were of a firmer texture, it was always electri- 

 fied vitreously and the glass resinously, when sulphur was em- 

 ployed as the rubber: and most generally the same effect followed 

 the use of gilt paper. 



' If an electrified ribin were brought near to an insulated plate 

 of lead, it would be very feebly attracted. If then a finger were 

 brought nigh to the lead, a spark might be observed to pass, and 

 the ribin was powerfully attracted, but showed no further sign 

 of electric excitement after coming in contact with the metal. 

 On their separation, however, both substances appeared again 

 electrified, and a spark passed between the plate and the finger. 



' If several ribins of the same color were placed on each oth- 

 er upon a smooth conducting surface, and rubbed with a ruler, 

 each, on being taken singly up, gave out sparks at its point of 

 separation from the others; and on the removal of the last ribin, 

 a spark would equally pass between it and the conductor. If all 

 were drawn from the plate together, they cohered in one mass, 

 which was resinously electrified on both sides. If after this they 

 were laid together on a rough conductor, and then separated sing- 

 ly, beginning with that which had been at the bottom and next to 

 the smooth conductor, sparks appeared as before, and all the ribins, 

 with the exception of that at the top, were electrified vitreously. 

 If friction were applied to them upon the rough conductor, and 

 all were taken up without separation, the intermediate ribins ac- 

 quired the electric state of either the highest or lowest, according 

 as the separation was begun with either the one or the other. 

 When two ribins were removed together from the rest, they 

 clung to each other, and exhibited none of those indications of 

 excitement which one, if taken alone, would have shown. When 

 these two were separated, that which had been the outer one was 

 found to have acquired electricity of an opposite nature to that of 

 the remaining undivided ribins, but in a much weaker degree. 



' Several ribins were placed upon a metallic plate, which was 

 charged with ielectricity by means of a glass globe and a pointed 



