376 
Loan Collection of Scientific Apparatus 
[July, 
This section also contains : — 
Balance used by Cavendish. — This balance, of rude exte- 
rior but singular perfection, was made by Harrison, according 
to the plan and by order of Henry Cavendish, and passed 
at his death to his cousin and heir, Lord George Cavendish. 
By him it was presented to Sir Humphry Davy, together 
with the greater part of Mr. Cavendish’s philosophical ap- 
paratus. Presented to the Royal Institution of Great 
Britain by Mr. Felix R. Carden. 
Balance used by Dr. Thomas Young and Sir Humphry 
Davy.— A balance made by Fidler for the Royal Institution. 
Balance used by Sir Humphry Davy. — Presented to Prof. 
Roscoe by Mrs. F. Crace-Calvert. 
Balance used in his experiments by Dr. Joseph Black, 
Professor of Chemistry in the University of Edinburgh, from 
1766 to 1799. 
Pneumatic trough used in his experiments by Dr. Joseph 
Black. 
Glass chemical vessels (retort, bottle, and flask or re- 
ceiver) used in the chemical laboratory of the University of 
Edinburgh during the latter half of last century, showing 
the contrast between them and vessels used for similar pur- 
poses at the present day. 
Apparatus employed by the late Thomas Graham, F.R.S., 
Master of the Mint, in his principal researches between the 
years 1834 and 1866. The series is interesting as showing 
the simplicity of the appliances with which Graham worked, 
and by the aid of which he discovered fadts and established 
laws which have since proved to be of so much importance. 
Old cupellation furnace, supposed to have been the one 
used by Sir Isaac Newton, when Master of the Mint, in 
some experiments on the cupellation of silver. 
Touchstone for the assay of gold, formerly used in the 
Royal Mint. — The method is based on the fadt that the 
greater the amount of gold contained in an alloy, the 
brighter is the gold-yellow colour of a streak drawn with it 
on a black ground, and the less is it attacked by pure nitric 
acid or by a “test” acid. In ascertaining the richness of 
the alloy under examination its streak is compared with 
marks drawn with alloys whose richness is accurately 
known. 
Apparatus used by Faraday for the condensation and 
liquefadtion of Gases, consisting of condensing pump and 
connedtions, conducting and other tubes, gauges, sealed 
tubes for containing the liquefied gases, &c. 
Original tubes containing gases liquefied by Faraday. 
