Note on an observation by Gerlach of the Boiling 

 Point of a solution of Glauber's salt. * 



by 



Joji Sakurai, F. CS. 



Professor of Clieiuistry, Imperial University. 



A few years ago Dr. G. T. Gerlach (Zeit. anal. Cliem., 26? 113) 

 published a paper in which he mentions that steam, escaping' from a 

 boilino' solution of Glauber's Salt containini'' a crystalline maii'ma of 

 the anhydrous salt, sliows the temperature of 100°, Avhilst the liquid 

 is boiling at 82° or even at 72°. This observation appeared to me so 

 curious and so anomalous that I was induced to repeat his experi- 

 ments : the results, on the whole, confirmed Gerlach's observations as 

 to temperatures but, at tlie same time, deprived them of all exceptional 

 character. Gerlach describes his experiments in the following words : 



" 700 gr. of crystallized Glauber's salt were melted in an iron 

 vessel and kept boiling for some time. The vessel was then removed 

 from the lamp, and the li(jnid portion of its contents was poured otf 

 as completely as possible, whilst the separated anhydrous salt was left 

 in the vessel. The whole was allowed to cool to about 50°, before 

 the vessel was again heated. This vessel was now provided with a 

 tin-plate cover having two holes, through one of which a thermometer 

 passed nearly reaching the bott<:)m of the vessel, and through the 

 other a second thermometer which hang in the steam chamber over 

 the heated crystalline magma." 



" The liquid completely boiled at 82° (Die Flüssigkeit kam schon 

 bei 82°c. vollständig in's ivochen), whilst the escaping steam showed 



