SCIENTIFIC SUMMARY. 
431 
Butter 34-3 
Sugar of milk 4-0 
Caseum and phosphates ...... 3-5 
Water 58-2 
100*00 
The butter here is nearly in the same proportion as the waxy matter in 
the milk of Brosimum galactodendron ; and as fatty matters susceptible of 
being split into acids and glycerine are assimilable, it is easy to understand 
the nutritive properties of the latter . — Comptes rendus , August 12, 1878. 
CHEMISTBY. 
Atmospheric Hydrogen Peroxide . — There has recently appeared in the 
“ Berichte der deut. chem. Gesellschaft” a very exhaustive report by Em. 
Schone of Moscow on the amount of peroxide of hydrogen present in air 
and in atmospheric deposits. It is divided into four parts (see vol. xi. 
pp. 482, 561, 874, and 1028), and gives the details of a lengthy investi- 
gation, extending from July 1, 1874 to June 30, 1875; it is one which 
has evidently been conducted with wonderful patience and care. During- 
the year he examined 215 specimens of rain and hail, and snow and sleet 
were tested on 172 occasions, making altogether 387 specimens submitted to 
examination. Seven samples of rain and 86 of snow appeared to contain 
no peroxide, or so small a quantity that it was left open to doubt and was 
recorded as O. The deposits brought by the equatorial currents always 
contained more peroxide than those falling at times when the polar current 
opposed them ; and when the polar stream of air predominates the relatively 
smallest yield of peroxide is obtained. The amount attained a minimum in 
December and January, very slowly increased till April, was very much 
higher during May and June on to July, when it culminated. During the 
next three months it fell rapidly, and in November again very slowly 
approached the minimum. The hail of summer contained a comparatively 
large amount of the peroxide, although it is less abundant in hail than in 
rain ; and the winter rain yields more of this compound than snow falling 
at the same period. The total amount of hydrogen peroxide which reached 
the earth’s surface during the year is computed by the author to have 
amounted to 109-4 milligrammes to the square metre, that is to say in 599-9 
litres of water, or 1-049 kilog. to the hectare. The peroxide present in the 
air in a state of vapour was collected and determined by producing artificial 
dew with the aid of freezing mixtures, and it was found that the rise and 
fall in the amount so obtained corresponded and went hand in hand with 
the numbers obtained by testing the atmospheric deposits. The diurnal 
variation was studied, and it was ascertained that the maximum amount was 
present at about four o’clock in the afternoon, after which it diminished, the 
minimum being attained between midnight and 4 a.m. The air of a large 
hall, which had been unoccupied for four weeks and the windows of which 
were closed but were not air-tight, was observed to contain an average of 
