182 FERMEXTATION. [VII. 



Ure has constructed an instrument of the same kind, similar 

 in principle to that of Conatj, (Phar. J. Trans, vii. 166.) 



Dilatometer. — Silbermann (Comptes Rendus, 1848) has in- 

 vented an instrument for determining the relative quantity 

 of each liquid in mixtures of water and alcohol. It is called 

 a dilatometer, and derives its principle from the fact, that the 

 dilatation of alcohol is three and a half times greater than that 

 of water, at temperature from 77° to 122° F. For example, 

 if the bulb of a thermometer-tube be over-filled with alcohol 

 and heated to 122°, it will be seen that the liquid rises in the 

 tube three and a half times higher than would the same quan- 

 tity of water under like circumstances. So, also, any mixture 

 of the two would give a mean point of dilatation, approximat- 

 ing that of the alcohol or water, according as either may 

 preponderate. Thus, by making the water point 0°, and 

 noting severally and consecutively the degree of dilatation 

 of a series of 100 mixtures, commencing with water 99 and 

 alcohol 1, and ending with alcohol 100, water none, a cen- 

 tesimal alcoholometric scale may be graduated so as to show 

 at a glance the proportion of either in any mixture of the two 

 liquids. 



Other scales may be adopted upon the same principle, to 

 determine the ratios of any other two liquids differing in their 

 degree of dilatation. 



The dilatometer is particularly applicable for testing wines. 

 The particulars as to its construction and use are given in the 

 original paper. 



Distilled Liquors and Fousel-oil. — To free them readily 

 from fousel-oil, Peters recommends a hogshead with a false 

 bottom to be half filled with well-ignited charcoal, the top of 

 this to be strewed over with lOSb boneblack, and SSb black 

 oxide of manganese, and the whole to be filled up with char- 

 coal. The hogshead is to be filled with brandy, whisky, &c., 

 which is to remain in it for 3 days, and then drawn off. That 

 which first runs off cloudy is to be redistilled, but this opera- 

 tion will not be again required. The vessel thus prepared 

 will last 12-15 months. 



