of Edinburgh, Session 1880-81. 
199 
Monday , 4 th April 1881. 
Pkofessok BALFOUK in the Chair. 
The following Communications were read 
1. On the Pressure-Errors of the “ Challenger” Thermometers. 
By Professor Tait. 
(This paper will appear in the Challenger Reports.) 
While at work during the past session in the Berlin Laboratory, 
it was suggested to me by Professor Hofmann, that I should exa- 
various degrees of heat. The thiofonnanilid employed was pre- 
sulphide of phosphorus, the resulting mass was treated with dilute 
caustic soda, and the alkaline solution of thiofonnanilid thus ob- 
tained was mixed with excess of hydrochloric acid, when impure 
thioformanilid separated out ; this was purified by crystallisation 
from hot dilute alcohol. The crystals thus prepared melted at 
137°-138° C., the melting-point of pure thioformanilid being 
137 '5° C. (Hofmann). 
Fifteen to twenty grains of thioformanilid were heated in a sealed 
tube to 180° C. for from six to seven hours. At the end of this 
time the tube was found to contain a confused mass of crystals, 
with a small quantity of a colourless liquid, and on opening the 
tube a considerable amount of sulphuretted hydrogen was evolved. 
The solid mass dissolved readily in alcohol, leaving no residue, but 
it was impossible to obtain crystals from this solution. When, 
2. The Action of Heat on Thioformanilid. 
By W. W. J. Nicol, M.A. 
c 6 H 5 
phenylformamid CHO with penta- 
H 
2 o 
VOL. XI. 
