284 Dr, Beddoes*s Account of fome new Experiments 
Spirit of nitre* diluted in the manner defcribed by Mr. 
Cavendish (Phil. Tranf. vol. LXXVI. part I.), having re- 
duced the thermometer to - 3 0 , fal ammoniac was added, 
upon which it fell to - 15 0 . 
Nitrated volatile alkali, during its folution in water, reduced 
the thermometer 35 degrees (from 50° to 15°); but the cold 
was not increafed by fal ammoniac or nitre. 
Mr. Walker’s mod: remarkable experiment w T as made on 
the 2 1 {1 of March, 1787, when he found that nitrous acid, 
when poured upon Glauber’s fait, produced effects nearly 
the fame as when it is poured on pounded ice ; and that the 
cold, thus produced, is rendered hill more intenfe by the addi- 
tion of fal ammoniac in powder. 
Mr. Walker, by many trials, difcovered that the bed: 
proportion of thefe ingredients is the following : of concen- 
trated nitrous acid, 2 parts by weight, of water 1 part ; of 
this mixture cooled to the temperature of the atmofphere 
eighteen ounces, of Glauber’s fait a pound and an half (avoir- 
dupois), and of fal ammoniac twelve ounces. On adding the 
Glauber’s fait to the nitrous acid, thus diluted, the thermo- 
meter fell from 4-51° to - i°, or 52 degrees; and on adding 
the fal ammoniac it fell to - 9 0 , that is full 60 degrees. Ni- 
trated volatile alkali, employed indead of fal ammoniac, pro- 
duced a cold rather more intenfe. 
By means of this mixture, in a very few minutes, in the elabo- 
ratory before the clafs, I froze fome fpirits above proof, di- 
luted with an equal bulk of water ; and another gentleman 
this day funk the thermometer 68 degrees. 
On April 20, 1787* Mr. Walker effected the congelation 
of quickfilver by a combination of thefe mixtures, without a 
particle of fnow or ice. When he began his experiment the 
temperature 
