660 REPOHi— 1887. 



8, On the present Aspect of tJie Question of the Sources of the Nitrogen of 

 Vegetation. Bg Sir J. B. Lawes, F.B.8., and Professor J. H. 

 GiLBEET, F.B.8. 



9. Dispersion Eiiuivalents and Constitutional Fornndcc. 

 Bg Dr. J. H. Gladstone, F.B.S. 



10. On a new and rapid Method of Testing Beer and other Alcoholic 

 Liquors. Bg Dr. William Bott. 



At a meeting of brewers recently held at Graz,in Austria, Professor H. Scliwarz 

 gave a popular lecture on a new process of estimating the strength and value of 

 alcoholic liquids. The method more particularly applies to beer, but can also be 

 used with other alcoholic fluids ; and as it claims the advantage of being equally 

 simple and rapid, and moreover does not require any special chemical knowledge on 

 the part of the operator, it would prove very valuable in the hands of Custom- 

 house officers, pubUcans, or other people who are frequently called upon to test 

 alcoholic liquors. The whole analysis can be done in three minutes, and consists in 



(1) A determination of the specific gravity by means of an accurate hydro- 

 meter ; 



(2) A determination of the index of refraction (this can be very readily done by 

 anybody with one of the so-called Abbe Zeiss refractometers, manufactured by Carl 

 Zeiss at Jena, Germany). 



From these two determinations we can easily obtain the difference between the 

 specific gravity of the liquor and that of pure water, also the difl'erence between 

 the respective indices of refraction of the liquor and pure water. Let .\ denote the 

 diiTerence between the specific gravities, and B that between the indices of refraction 

 of the liquor and pure water respectively ; then the general formula is 



a.v — bg= A. 



c.v + dy = 'Q 

 w^here .r = 9^ of extract 

 and 7/ = 96 of alcohol. 



(t, b, c, and d are con.stants, viz. : 



« = efiect of 1% of extract upon specific gravity. 

 6= ,, alcohol ,, 



c = „ extract upon refraction 



d= „ alcohol „ 



These constants have been determined by a series of very careful experiments 

 and found to be 



a = 0-00393; i = 000103; c = 0-00150; (? = 0-00002. 



The only objection to the above method is the expense of an instrument for the 

 determination of the index of refraction ; still in cases where a great number of 

 analyses have to be made, the saving of time and trouble would amply repay the 



first cost. 



11. On some Organic Vanadates.^ Bg John A. Hall. 



I have obtained a series of organic ortho-vanadates by the action of an alkyl 

 bromide on silver ortho-vanadate. These bodies are yellow liquids, which decom- 

 pose on distillation under the ordinary pressure, but the lower members can be 

 distilled under reduced pressure. 



Methyl vanadate could not be obtained. 



Ethyl vanadate boils at 150° C. under a pressure of 120 mm. The vapour 

 density is normal. The specific gravity is 1-167 at 17-5° C. 



Printed in extcnso in the Joiirn. of the Chem. Soc. Oct. 1887. 



