107 
The precise form of the electrical machine used by Franklin ap- 
pears to be a matter of some doubt. Parts of several machines are 
known, all reputed to have belonged to Franklin. ‘Three or four 
quite similar frames are in existence, all provided with multiplying 
wheels for giving rotation to the electric used, which was mounted 
upon an axis placed above the wheel. One of these frames is in 
possession of the Franklin Institute, another is owned by the Uni- 
versity of Pennsylvania, and a third is in the physical cabinet of 
the College of New Jersey, at Princeton. In only the first of these, 
however, is the electrical portion preserved. The electric isa glass 
globe, having a leather cushion for its rubber and provided with a 
curved rod for the collector. Moreover, these frames or stands all 
resemble very closely that which is described and figured as ‘‘ the 
cylindrical machine as constructed by Franklin,’’? in Snow Harris’ 
Frictional Electricity.* But, as shown, this latter machine is pro- 
vided with a cylinder as the electric, and not a globe. Again, in 
January, 1879, Miss Mary D. Fox presented to the University of 
Pennsylvania several pieces of electrical apparatus, said to have be- 
longed to Franklin, and to have been deposited at the house of her 
father, George Fox, at Champlost, to whom they were bequeathed 
by William Temple Franklin, the grandson of Benjamin Franklin, 
together with many of his valuable papers, now in possession of the 
American Philosophical Society.t One of these pieces of apparatus 
I have the pleasure of exhibiting. It is evidently the collector (or 
prime conductor, as it was formerly called) of an electrical ma- 
chine; and, as is evident from its construction, could have been 
used only with a machine provided with a plate electric. 
In the earliest electrical machine, made in 1672 by Von Guer- 
icke, the electric consisted of a globe of sulphur, mounted on a 
horizontal axis and rubbed with the hand. In 1709, Hawksbee 
replaced the sulphur globe by one of glass. Franklin, in his first 
letter to Collinson, thus speaks of his electrical machine: ‘‘ Our 
spheres are fixed on iron axes which pass through them. At one 
end of the axis there is a small handle with which you turn the 
spbere like a common grindstone. ‘This we find very commodious, 
as the machine takes up but little room, is portable and may be en- 
* A Treatise on Frictional Electricity in Theory and Practice, by Sir William Snow Harris, 
F.R.S., London, 1867, p. 104. 
+See Proceedings Amer. Philos. Soc., i, 253, July 17, 18:0. ‘‘The Franklin papers were 
bequeathed by will to George Fox, father of C. P. Fox, by Temple Franklin, grandson of 
Benjamin Franklin.” 
