368 Miscellaneous Intelligence. 



thermometer is suspended in the Hquid by the left hand, the 

 vessel is to be held by its neck in the right, and a rapid 

 whirling motion given to it, to accelerate the solution. 

 Whilst this is doing, the thermometer falls rapidly ; it is to be 

 observed with attention, and the lowest degree to which it 

 passes noted. Suppose this 12°.8 (58.04 Fahrenheit.) The 

 diminution of temperature d is consequently 20°.4 — 12°.8 

 = 70.6 (13.68 Fahrenheit,) and the chloride of potassium is 

 equal to ^""••^';'i~' "" := 60. 



This process, which scarcely requires ten minutes to be com- 

 pleted, is susceptible of the greatest precision, and, in conse- 

 quence of its simplicity, may readily be employed in the arts. 

 It is especially advantageous in the preparation of nitre, for the 

 analysis of the salts which are deposited during the evaporation 

 of the water, and which are the chlorides of potassium and 

 sodium, in very variable proportions. 



Nitre produces also much cold by its solution in water. 

 The means which have been noticed are also applicable to the 

 analysis of a mixture of nitre and common salt. In general, 

 this method may serve for all those bodies which produce very 

 unequal diminutions of temperature by solution in water, or in 

 any other liquid. — Annalesde Chimie., XII., p. 42. 



3. Discoienj of pyroligncous Acid. 



Mr. Editor, — Sir, — In the Revue Encyclopidique, M. le 

 Comte Chaptal has published an article de VlndustTie Frangoise, 

 in which, among other things, pyroligneous acid is enumerated as 

 being one of the discoveries made in the arts by the French. 

 Whenever priority of discovery is wrongfully claimed, it may be 

 well to point it out, that the merit of originality'tnay be attached 

 to its proper claimant. With this view, I have copied the follow- 

 ing statement from a work printed by Cooke, London, in the 

 year 1661, entitled, the Sceptical Chemist, in which it ap- 

 pears, that pyroligneous acid is of much earlier origin than 

 is commonly supposed, and that the fact of its forming sugar 

 of lead with minium was known one hundred and fifty-eight 

 years ago. 



