464 Scientific Intelligence, Sfc. 



that he had extended his observations to many inflammatoiy diseases, 

 and had found, uniformly, that inflammation of mucous and serous 

 membranes in all parts of the body, is attended by the secretion of 

 free acid. Hence the scientific method of removing this source of 

 irritation in such diseases, viz., by the local application of alkaline 

 solutions, as in erysipelas, inflammation of the urethra, &c. He 

 stated also that he had examined the chemical composition of the 

 membrane deposited in croup, and had found its principal constituent 

 to approach nearer the character of albumen than any other animal 

 substance, which would add some weight to the opinion of Donne, 

 that morbid products derive their origin from the free acid secreted 

 on the surface of the membrane upon which the product is deposited. 



Additions to the different Sections, 



We are indebted for the following reports to their respective authors. 



On a method for ascertaiyiinfj the strength of spirits, by Mr. 

 William Black. (The author of this paper is well known by his 

 valuable '' Practical treatise on Brewing and on Storing of JBeer, 

 deduced from forty years experience.") 



I believe it has for long been a desideratum with government to 

 find a more scientific and accurate mode of ascertaining the strength 

 of spirits than that now in use. A very slight inattention in the 

 method of using the hydrometer may make a difference of at least 

 five })er cent., and when the spirits are adulterated with sugar or 

 salts, that instrument is totally useless. It is a well known fact that 

 when equal quantities of proof spirits and water are mixed together 

 at a temperature of between 50" and 60° (Fahrenheit), the thermo- 

 meter, if immediately immersed in the mixture, will rise 9^ degrees. 

 I do not, however, think it is so generally known that the thermo- 

 meter rises more or less, according to the strength of the spirits, and 

 that it does so apparently in very regular progression, when the 

 spirits are between the strengths of 45 per cent, over and 45 per 

 cent, under proof. 



When spirits, 45 per cent, over proof, are mixed in equal quan- 

 tities with water, both being of the same temperature, i. e. between 

 50® and 00°, the thermometer, if immediately immersed in the 

 mixture, will rise 14° degrees ; but with the strongest alcohol, also 

 mixed with an equal quantity of water, it will not rise above that 

 temperature ; no further concentration therefore takes place, unless 

 more water be added, shewing, I should think, that alcohol can only 

 combine with water in atomic proportions, and that a certain portion 

 of that spirit must remain in the first mixture in an uncombined state. 



Every degree on the thermometer appears to indicate a difference 

 in the strength of the spirits of about 10 per cent ; thus if we mix 

 equal quantities of spirit, 10 percent, over proof, and water, both at 

 equal temperatures of about 55°, the thermometer will rise 10J° ; 

 with spirit 20^ over proof, mixed as above, it will rise 11 2°; and so 

 on — one degree for every 10 per cent, over proof, until it reaches 

 about from 40 to 45 over proof, when no further increase is apparent, 

 unless, as I have before stated, more water be added. 



