762 ETHYL. 



by a greater cold it became still thicker, and at 146 flowed 

 like melted wax. Alcohol of 0.820 froze easily ; ether under- 

 went no change by the lowest of these temperatures.* 



Alcohol boils at 173 (barometer 29.5 inches), and at higher 

 temperatures, in proportion as it is diluted with water. It is 

 remarkable, however, that the boiling point of a mixture of alco- 

 hol and water rises with the quantity of water to a certain point ; 

 alcohol of 96 to 99 per cent boiling at a somewhat lower tempe- 

 rature than absolute alcohol. In consequence of this, alcohol of 

 density 0.800 is increased in strength by boiling it : and hence 

 also, in the preparation of absolute alcohol, the first portions 

 contain always a little more water than those which follow. Alco- 

 hol has an agreeable penetrating odour, and is the intoxicating 

 principle of all spirituous liquors. The density of its vapour, 

 according to Gay-Lussac, is 1613, referred to air as 1000; it 

 contains eight volumes of carbon vapour, twelve volumes of 

 hydrogen, and two volumes of oxygen condensed into four 

 volumes, its combining measure, which gives the theoretical 

 density 1601. Alcohol is highly combustible, and burns with 

 a flame that is nearly colourless and free from smoke ; the 

 only products of its perfect combustion are water and carbonic 

 acid. 



Alcohol has a great attraction for water, which when anhy- 

 drous, alcohol attracts rapidly from the air. It also withdraws 

 water from animal substances, and thus preserves them. When 

 mixed with water, a very sensible evolution of heat occurs, and 

 always a diminution of bulk and increase of density, when 

 water and absolute alcohol are mixed in any proportions, 

 although on adding water to alcohol, already considerably di- 

 luted, an apparent expansion may be observed. The greatest 

 contraction occurs on mixing 1 atom of alcohol with 6 atoms of 

 water, when a definite hydrate is certainly formed ; 100 volumes 

 of this mixture contain 53.939 volumes of alcohol, and 49.836 

 volumes of water; consequently, 103.775 volumes are reduced 

 to 100 ; its density is 0.927 at 59.f 



Alcohol dissolves most of the gases, and several of them in a 



* Liebig's Annalen, vol. 37, p. 354 ; from Silliman's American Journal of 

 Science, 

 t Rudberg, Annales de Chim. etc. xlviii, 33. 



