144 Scientific Intelligence. 
centimeters of pure H,SO, previously diluted with its own 
volume of water and cooled, are carefully poured in under con- 
stant stirring, and the excess of potassic permanganate is then 
determined with a standard aN og of oxalic acid. Five deter- 
minations of a sample of potassic nitrite showed a variation of 
only ;3, of one per cent, and the same number of determinations 
of Sodic nitrite a variation of only ;35 of one per cent. 
Tn a careful series of experiments, Mr. — of the Jun- 
ior class, attempted to apply the same method, « der Dr. Kinni- 
cutt’s direction, to the estimation of the eplohies bas he did not 
obtain satisfactory results. 
irector of the Laboratory, Professor J. P. Cooxn, has 
continued his work on the Revision of the Atomic Weights. He 
has elaborated methods for determining se great rye the 
relations H: 0: Ag; H: 8S: Ag; H: eee be ; 
Br: Ag, fixing the relations between a8 Fi cae of each tae 
in a single series of determinations, Starting with the relatiog 
g: Br=108: 80 in regard to which there is a universal agree 
ment he is seeking to fix the relations of each value at once to 
two others, whose Tmutual pores are already known, as in his 
previous work on the relat n, 
Ag: Br: Sissi 00 : 80°00: 120°00. 
ee * This investigation cividalgs involves a great amount of 
abor; and since it must be a ong time ore the final results 
can be reached this announcement is made to prevent an unneces- 
rind io darn te of the work. In connection with this peti" 
tion the writer has developed a simple method of reo e 
weight of a pee for the buoyancy oe — tmosphere, which was 
described in the previous number of this Journal, and similar sub- 
ordinate results will be published Boitt time to time as the inves- 
tigation proceeds. 
nder the direction of Professor Cooke, Mr. C. P. WorcEsTER, 
of the graduating class, has determined the vapor density of the © 
: h : 
Density, Air=1. Theory, SbRs. 
7°96 
Antimonious chloride, ‘ 7°85 
Y b id 12°57 12°48 
« iodide, 17°59 17°33 
The first two values were obtained by a of air, the 
last by displacement of nitrogen, and the variations from theory 
cess. It therefore appears that in the state of vapor the mole- 
a of all three compounds have the same simple constitution. 
r. Worcester also determined the heat evolved in the familiar 
