108 
closed in a tight box when not in use. ’Tis true the sphere does 
not turn so swift as when the great wheel is used; but swiftness we 
think of little importance, since a few turns will charge the vial 
sufficiently.’’ He adds, in a footnote: ‘‘ This simple and easily 
made machine was a contrivance of Mr. Syng’s.’’ 
The addition of a metallic collector to the globe machine was 
made by Boze in 1742,* and the use of a leather cushion as the 
rubber was introduced by Winkler in 1744.+ And, although 
Hawksbee had used a cylindrical electric, yet it did not come into 
use apparently until Wilson again made use of it in 1752.{ It was 
not until 1756 that De la Fond § made a machine having a plate 
electric ; in which he was closely followed by Ingenhaus (1764),|| 
Cuthbertson (1770),4] and Le Roy (1772).** The addition of a 
multiplying wheel is generally attributed to Nollet, in 1746.,f 
In this connection, it is interesting to note that, with the elec- 
trical apparatus given to the University by Miss Fox, there was a 
set of copper-plate impressions of certain experiments in heat and 
electricity. As these engravings could not be identified with any 
of the researches made by Franklin, it was for some time doubtful 
what their origin was and what their connection with Franklin 
himself. Finally, several years later, in looking over the very com- 
plete antiquarian scientific library of Prof. H. Carrington Bolton, 
of New York, the writer observed that facsimiles of these plates 
served as the illustrations of a book entitled, ‘‘ Recherches Physiques 
sur le Feu. Par M. Marat, Docteur en Médecine et Médecin des 
Gardes du Corps de Monseigneur le Comte d’Artois. A Paris, Rue 
Dauphine, MDCCLXXxX, pp. 204 avec VI planches.’’ Thus estab- 
lishing the fact of scientific intercourse between Franklin and 
Marat, afterwards one of the chief actors in the French Revolu- 
ion.tt 
tion. tt 
* Die Electricitdt nach ihrer Entdeckung und Forgang, ete., Wittenberg, 1714. 
+ Gedanken von den Eigenschaften . .. . nebst Beschreibung zweyer neuen electrischen 
Maschinen, Leipzig, 1744. 
{A Treatise on Electricity, London, 1752. 
2 Precis des Phénomenes Electriques, 1754, 2d ed., p. 47. 
| Phil. Trans., xiv, 598, 1779. 
4 Harris’ Frictional Electricity, p. 68. 
*& Mémoires del’ Academie, Premiére Partie, p 499, 1772. 
+} Lecons de Physique, Paris, 1767. 
ttIn a memorandum made at Passy, December 13, 1778, Franklin says: “Received a 
parcel from an unknown philosopher [afterwards discovered to be Marat, of subsequent 
notorious memory], who submits to my consideration a memoir on the subject of elemen- 
tary fire, coutaining experiments in a dark chamber. It seems to be well written, and is 
in English, with a little tincture of French idiom. I wish to see the experiments, 
without which I cannot well judge of it’’ (Memoirs, Vol. ii, p. 90). 
