1012 
into ammonia, is also in harmony with the structure of the weakest 
base (Il). For, when the OH-group is attached to nitrogen it may 
be reduced more readily than when attached to carbon. Hence, the 
stronger base (I) ought, on reduction, to yield methylamine. This, 
in fact, has proved to be the case when the methyl derivative is 
reduced, anyhow to a large extent. . 
These matters will be further explained in a more extended 
article in the Rec. tr. Chim. d. Pays-Bas in which the analytical 
figures and the titration and rotation figures of the velocity measu- 
rements will be also given. 
Oximes being amphoteric electrolytes, I have tried to determine 
also the dissociation constant of the acid. From the dried ethereal 
solution of formaldoxime a small quantity of a solid sodium salt 
is precipitated by sodium methoxide. This however, is so unstable 
that I have not been able to sufficiently purify it to execute trust- 
worthy velocity measurements with it. 
‘s-Hertogenbosch, Nov. 1915. Lab. 8. B.nSrS1j10: 
Astronomy. — “On the orbital planes of Jupiter's Satellites, as 
derived from measurements made at Berlin. By Prof. W. 
Der Sirter. 
(Communicated in the meeting of December 18, 1915). 
In the years 1906 to 1909, with the RrPsorp micrometer attached 
to the nine inch telescope by Fraunnorer of the Observatory at 
Berlin, Dr. P. Gutanick made three valuable series of observations 
of the four old satellites of Jupiter, from which he derived the 
position of the orbital planes of these bodies.) The observations 
were compared with Sampson’s tables. As Dr. Gurunick remarks, 
his results, especially those for the satellites I] and IV, agree better 
with my theory of 1908°*) than with Sampson’s. The comparison 
with my theory made by Gurunick was however of a preliminary 
nature, and it appeared desirable to carry it out more in detail. 
The immediate results from GurHrick’s discussions are the correc- 
tions to the adopted elements, which are given on the pages 121 
and 122 of his paper, together with the resulting final inclinations 
and nodes referred to the adopted fundamental plane. This funda- 
1) Veröffentlichungen der Kön. Sternwarte zu Berlin—Babelsberg. Band I. Heft 3. 
2) These Proceedings, March 1908; Vol. X, pages 653—673 and 740—729. 
