(op) 
Mr. J. J. HursMAN, dairy-inspector took part in the experiments 
with the beet-foliage. 
Government-Agricultural-Experiment-Station 
Groningen. 
EXPLANATION OF THE GRAPHIC REPRESENTATIONS, 
>) 
Se 
Q 
g. I, Influence of feeding with beet-foliage on the R.M.W.-numbers (amount of 
volatile fatty acids) of milkfat. 
The dates of sample-taking are put down on the, X-axis, the R.M.W.-numbers 
on the Y-axis. 
Fig. Il. Influence of feeding with beet-foliage on the refractionnumbers of milkfat. 
On the X-axis the dates, on the Y-axis the refractionnumbers have been put down. 
Fig. ILI. Influence of feeding with sugar on the R.M.W.-numbers of milkfat. 
On the X-axis the dates, on the Y-axis the R.M.W.-numbers have been put down. 
Fig, IV. Influence of feeding with molasses and with sugar on the R.M.W.-numbers 
of milkfat. 
On the X-axis the dates have been put down; on the Y-axis the R.M.W.-numbers. 
Chemistry. — “The densities of mixtures of hydrazine and water.” 
By Mr. J. W. Dito. (Communicated by Prof. C. A. LoBRY 
DE BRUYN). 
Some years ago I was able to prepare hydrazine, a substance 
previously unknown in the free state (discovered in the form of its 
compounds by Curtius) and to study many of its properties 1). 
Several physical constants [melting point, boiling pomts at different 
pressures, specific gravity, index of refraction *), critical temperature 
and heat of dilution *)| were then determined. 
The study of hydrazine has not since been continued. Still it 
was deemed of importance to again take up the study of a substance 
which belongs to a class of liquids of comparatively simply constitution : 
H,N.NH, closely related to ammonia, miscible with water with 
considerable evolution of heat and according to several of my expe- 
riments, a good solvent for many salts. 
Mr. Drro has now in the first place commenced with the deter- 
mination of the densities of mixtures of water and hydrazine. This 
was of all the greater importance because Curtius had stated that 
1) Versl. Akad. Juni 1895. Recueil, 13. 433, 14. 88, 15. 174. 
*) By Prof. J. F. EÉYKMAN. 
3) With Dr, RrICHER. 
