DECEMBER 29, 1899. ] 
must be measured. Some exceptional reader 
in a community may exceed in intelligence the 
sum of intelligence of all other readers, and 
even some illiterate may go beyond a number 
of literates. Hence only by the special study 
of individuals, and adding the results, can the 
sum total of intelligence for any community be 
found. But this is the task of psychology, not . 
sociology, whose field is objective fact, social 
actualities like illiteracy, crime, etc., and their 
concomitant variations. Sociology can deter- 
mine how many people read, and what they 
read, and the concomitant variation between 
the circulation of yellow journals and increase 
of crime ; but it cannot measure the intelligence 
or the emotion implied, for the psychical illu- 
mination of social phenomena can come only 
from psychology. 
Hiram M. STANLEY. 
LAKE Forest, ILt., December 2, 1899. 
NOTES ON INORGANIC CHEMISTRY. 
A PECULIAR interest attaches to ammonium 
cyanate from the fact that it was the sponta- 
neous eonversion of this salt into urea, which 
first bridged over the gulf between the inor- 
ganic and organic, and in the hands of Wohler 
gave the great impetus to the study of organic 
chemistry. Owing to its instability it has been 
very difficult to prepare ammonium cyanate in 
a pure condition. It is shown, however, in the 
Proceedings of the Chemical Society (London), 
by J. Walker and J. K. Wood, that the sub- 
stance may be readily formed by mixing the 
cooled solutions of ammonia and cyanic acid in 
ether. It is also formed when the vapors of 
ammonia and cyanic acid are brought into con- 
tact, provided the reacting gases are sufficiently 
diluted with some indifferent gas. The trans- 
formation of solid ammonium cyanate into urea 
is facilitated by heat and very greatly accel- 
erated by presence of moisture. 
In the same Journal, G. Dean describes a new 
series of atomic weight determinations of nitro- 
gen. They are peculiar in their use of silver 
eyanid as the salt analyzed. The other atomic 
weights involved are those of potassium and 
bromin, hence the accurately determined Stas 
figures were available. The value found was 
SCIENCE 
975 
N=14.031 which is somewhat lower than the 
weight accepted by Clarke 14.04, and that by 
Richards 14.045. (O=16). 
In a recent number of the Comptes Rendus, 
Moissan has described the formation of ozone by 
the decomposition of water by fluorin. If the 
temperature of the water into which the fluorin 
is led, is kept at or below zero, it is possible to 
get over 14 per cent. ozone (by volume) in the 
gas over the water. Moissan points out the 
possible practical application of this method, 
for though the electrolytic production of fluorin 
from hydrofluoric acid is still a rather difficult . 
operation, it is not an expensive one. The 
ozone formed in this process has the advantage 
of being completely free from the oxides of 
nitrogen. 
Or late years several explosions have taken 
place in factories where aluminum-bronze pow- 
der is ground. Investigations as to the cause 
of these explosions have been made by Stock- 
meier, and are reprinted in the Chemical News. 
The powder is perfectly stable, but its mixture 
with potassium chlorate will detonate even by 
rubbing. Bronze in contact with water decom- 
poses it forming hydrogen, and it is to the pres- 
ence of the hydrogen that explosions are prob- 
ably due. The powder is hygroscopic and the 
dry powder can absorb 1.4 per cent. moisture 
from the atmosphere. Then in grinding up 
five or six kilos of bronze powder there could 
be moisture enough present to generate forty 
to fifty liters of hydrogen. A series of precau- 
tionary rules is proposed, the most important _ 
of which require dryness and absence of dust in 
the air about the grinding machine. 
PROFESSOR E. T. ALLEN of the Missouri School 
of Mines calls attention in the Chemical News to 
a curious case of corrosion of gold plated weights 
which had been put away for the three sum- 
mer months in a safe. The weights were 
covered with a white substance which proved 
to contain zinc and to be largely organic. The 
suggestion is made that the corrosion was caused 
by mould, the gold plating being, perhaps, not 
completely impervious, and the most positive 
metal, zinc, being removed from the brass. It 
appears to be well established now that certain 
hard waters have the property of dissolving the 
