ALCOHOL. 



419 



SPIRIT OF WINE, OR ALCOHOL, is not a natural product. It is found 

 by the decomposition of grape-sugar by fermentation. There is a series of 

 alcohols which exhibit a regular gradation, founded, so to speak, upon one, 

 two, or three molecules of water. They are called respectively alcohols, 

 glycols, and glycerins. Thus we have 



Alcohols. 

 Methylic alcohol. 

 Ethylic 

 Prophylic 

 Amvlic 



Glycols. 



Enthelein glycol. 

 Prophylene 

 Butylene 

 Amylene ' 



Glycerins. 



(Ordinary Glycerine is the 

 only one known.) 



The cetyl and melissylic alcohols are contained in spermaceti and bees-wax 

 respectively. The usual alcohol is the Vinic, a transparent, colourless liquid, 

 which is the spirituous principle of wine, spirits, and beer, and 

 if when sugar is fermented the alchol and carbonic acid remain. 



|f Spirits of wine has a very powerful affinity for water, and 



thus the use of stimulants in great quantity is to be deprecated, 

 for alcohol absorbs the water from the mucous membranes of 

 the stomach and the mouth, making them dry and hard. The state 

 of " intoxication," unfortunately so familiar, is the effect produced 

 by alcohol upon the nerves. We append a list of the beverages 

 which are most in use, and the percentage of alcohol in each 

 according to Professor Hart : 



Port . 



Madeira 



Sherry 



15 per cent. 

 H'5 



Claret 



Ale 



Porter 



8 per cent. 

 6 

 5 



Spirit of wine is contained in many mixtures, and for the purpose 

 of ascertaining how much alcohol may be in wine, or any other 

 liquid, a hydrometer is used (fig. 432). This instrument consists 

 of a glass tube with a bulb at the end. It is put into water, and 

 the place the water "cuts" is marked by a line on the stem, 

 and called zero o. Spirit of wine has less specific gravity than 

 water, so in absolute alcohol the instrument will sink lower than 

 in water, and will descend to a point which is marked 100 . In 

 any mixture of alcohol and water, of course the hydrometer will 

 rise or sink between the extreme points accordingly as the mixture may 

 contain less alcohol or more. So a scale can be furnished. The instrument, 

 as described, was invented by MM. Gay-Lussac and Tralles, and called 

 the " percentage" hydrometer. There are many other instruments marked 

 in a more or less arbitrary manner. We append a comparative table 

 of a few hydrometers. (Sex page 420.) 



ETHER, or sulphuric ether, is a mixture of spirits of wine with sulphuric 

 acid, and distilled. It loses water, and the product is ether, which is volatile, 

 and transparent, with a peculiarly penetrating odour. It will not mix with 

 water, and if inhaled will produce a similar effect to chloroform. 



