410 ' PHU-OSOPHICIAi TRANSACTIONS. [aNNO 1747. 



tQ 192 degrees, and as the ratio between Sir Isaac's degrees and Fahrenheit's is as 

 34 to J 80, it necessarily follows, that the difference of heat between the hot iron 

 and the cold mixture is 1040 degrees; and yet this vast difference makes no alte- 

 ration in the appearance of the electrical flame. We find likewise, that as the 

 fire, arising from the refraction of the rays of light by a lens, and brought to a 

 focus, is observed first at some small distance from their surfaces, to set on fire 

 combustible substances; tjUe same effect is produced in like manner by electrical 

 flame. 



A Sequel to the Experiments and Observations tending to Illustrate the Nature 

 and Properties of Electricity. By the same. N° 484, p. 704. 



Mr. W. caused a machine to be made for electrical purposes; the wheel of 

 which was 4 feet in diameter. In the periphery of this wheel were cut 4 grooves, 

 corresponding with 4 globes of 10 inches diameter, disposed vertically at about 3 

 inches distance from each other. One, two, or any number of these globes 

 might be used at pleasure. They were mounted on spindles of 1 inches diameter, 

 and their mean motion round their axis was about 1 100 times in a minute. As 

 it is next to impossible to have these globes blown and mounted perfectly true, he 

 had the leather cushions, with which they were rubbed, stuffed with curled hair, 

 an elastic substance, that the globes in their rotations might be as equally rubbed 

 as possible. 



He lined one of these globes to a considerable thickness, with a mixture of 

 wax and resin, to observe whether the electricity would be the sooner or more 

 strongly excited ; but no difference was found in the power of this globe from 

 the others, which were without this treatment. 



The power of electricity is increased by the number and size of the globes to 

 a certain degree ; but by no means in proportion to their number and size ; there- 

 fore, as the bodies to be electrified will contain only a certain quantity of elec- 

 tricity ; when that quantity is acquired, which is soonest done by a number of 

 globes, the surcharge is dissipated as fast as it is excited. 



After the globes had been a few times used, he found he had a much greater 

 quantity of electrical power, with much less labour than when he used only 

 tubes. He could attract and repel light substances at a much greater distance 

 than before; fire spirits of wine, camphor, and all other substances whose vapours 

 were inflammable, with great ease, and at any distance, with non-electrics 

 placed on originally-electrics, though not equally easy when the weather was 

 moist. 



He discovered with this machine, and communicated to several members of 

 this Society, several of the experiments said to be first made by M. le Monnier 



