ALCOHOL. 213 



molasses. Most of the distilled liquors contain from 40 to 

 50 per cent of alcohol. By repeated distillation and rectifi- 

 cation pure alcohol is obtained. Pure alcohol is not largely 

 used, the ordinary commercial alcohol being about 91 per 

 cent alcohol. The effects of alcohol on the human system 

 will be treated a few paragraphs later. 



Physical Properties of Alcohol. Alcohol is a clear 

 liquid of .79 specific gravity. It boils at 173 F., and does 

 not freeze above 200 F., hence is often used in thermome- 

 ters. Alcohol dissolves gums and resins, and many sub- 

 stances which are insoluble in water. 



Chemical Properties of Alcohol. Alcohol is composed 

 of carbon, hydrogen, and oxygen (C 2 H 6 O). In composi- 

 tion the alcohols (for there are many kinds of alcohol) 

 resemble fats. In both there is only a small proportion of 

 oxygen to the amount of carbon and hydrogen. For this 

 reason both burn with great readiness and produce a large 

 amount of heat. Alcohol burns with a nearly colorless, 

 but very hot, flame, and does not produce soot ; hence the 

 alcohol flame is very useful in delicate work, such as 

 watch-making, etc. 



Physiological Effects of a Moderate Dose of Alcohol. 



A moderate dose of diluted alcohol or ordinary alcoholic 

 drink usually has about the following effects, especially 

 upon those not accustomed to its use. First, a dilation of 

 the blood tubes of the face and of the mucous lining of the 

 stomach ; for a very short time a quickened, and perhaps 

 more forcible, heart beat; nervous excitement, shown by 

 restlessness and talkativeness ; followed by more or less 

 dullness or drowsiness, usually followed by a depressed 

 feeling on the next day. 



