134 PUBLIC HEALTH CHEMISTRY 



acid (free from alcohol). A rose tint appears, which is 

 compared with that from 10 c.c. of standard solution of 

 furfurol (0-005 g 011 - P er litre) similarly treated. From I 

 to 3 parts per 100,000. Formula: C 4 H 3 OCHO. 



Fusel Oil (Amyl Alcohols, C 5 H,,'OH). Spirits should 

 never contain more than o-i per cent amyl alcohol, as such. 

 Tests : Distil off ethyl alcohol from 100 c.c. on water- 

 bath and take residue. Add an equal bulk of water, cool, 

 and extract with ether. Let ether evaporate at room 

 temperature and divide residue into three parts. 



1. Heat one portion with sulphuric acid and a little potas- 

 sium bichromate ; a smell of valerianic acid is obtained. 



2. Heat with sulphuric acid and sodium acetate, when 

 the odour of jargonelle pears (acetate of amyl) is got. 



3. Warm with double its volume of strong sulphuric acid ; 

 violet-red colour of amyl sulphuric acid is formed. 



Aldehydes. Vary from 10 to 40 parts per 100 litres of 

 alcohol (100,000 parts). 



Higher Alcohols. From 100 to 250 parts per 100,000 

 parts of absolute alcohol. 



Total Secondary Products, or " the co-efficient of im- 

 purities," is the sum total of the free acid, aldehyde, fur- 

 furol, ethers, and higher alcohols. According to the Lancet 

 Commission this co-efficient varies for a specially fine 

 brandy from 300 to 646, bat may tall to 250 per 100,000 of 

 absolute alcohol in inferior but genuine brandy. Grain and 

 beet spirits are comparatively free of secondary products, 

 furfurol especially being absent. Gin is also low in total 

 secondary products. Jamaica rum is very high in ethers 

 (400 grm. of ethyl acetate per 100 litres of absolute alcohol 

 present) and contains more acids and furfurol than brandy. 

 Whisky closely resembles brandy, but the furfurol is high. 



Specific gravity is frequently ascertained by Sykes' hydro- 

 meter, the temperature of the liquid being noted, and the 

 result obtained from special tables, which give the amount 

 that the sample is over or under proof. If there is much 

 solids the spirit must be distilled as for beer and wine. 



Methyl Alcohol, CH 3 'OH (wood spirit). Is a liquid 

 which boils at 66 C., and at 20 C. has a sp. gr. of 796. 

 From it are derived formaldehyde (H'CHO) and formic 

 acid (H-COOH). 



