Ohemistry and Physics, — 395 
1 2 8 
hydroxamic acid N(C,H,O,)(C,H,O)OH, with two replacements; 
1 2 3 
and dibenzanishydroxylamine N(C,H,O)(0,H,0)0(C,H,0,), 
1 3 
benzanisbenzhydroxylamine N(C, H,C)(C, Hy O 2)O(C, H,0O), and 
anisdibenzhydroxylamine N(C, ti sO)(E. i ,2)O(C, i ,;0), when 
three atoms are thus exchanged. Nowi ydrogen atoms 1 and 
in hydroxylamine are precise equivalents, the first two of the above 
named five compounds are identical; if not, they are only isomeric. 
If hydrogen atoms 2 and 3 are equivalents. then the third and 
fourth of the above a are identical; but they are only 
isomers, if they are n Lastly, if hydrogen ‘atoms 1 and 3 are 
equiv alent to each fers the third and fifth of these compounds 
must be the same ; but if these atoms are not precisely identical 
in function, the compounds must be isomers. The author has 
roved the most important point, that benzanishydroxamic _ 
ng es Segre mic acids are not identical, but are isomeri 
such atoms in hydroxylamine. ‘Lossen assigns therefore to dbens- 
H 
hydroxamic acid the formula C,H,O— N-0-C ,H,O and to 
H 
dianishydroxamic acid that of C,H,O,— My 
author promises further researches to fix the position of the replac- 
ing radica 2 oe the monohydroxamic acids.—Liebig’s Ann., clxxv, 
271, Jan., 
. In fluen nce of Pressure on Combustion.—M. 1.. Cat ETET has 
studied the — of a pressure of 30 to 35 atmospheres on the 
e air was éouiienied by pumps in which the ‘pistons were fixed 
r 
> 
and the cylinders movable, a layer of wat glycerine at the 
same time cooling the gases so as to protect the packing from the 
heat, and preventing leakage. The reservoir consisted of a hol- 
low cylinder with four apertures; the first admitted the gas, the 
second allowed it to escape, the third admitted the manometer- 
tube, and the fourth was closed by . thick glass plate to allow of 
observation of the interior, The iatter had a di ameter of 10 cms. 
and a capacity of Hi 4 liters. Placin a lamp in this space, the 
brightness increased with the pressure of the air. The base of the 
ame, which under the ordinary pressure is blue and transparent, 
became white and ver bright; but soon the appearance change 
and thick clouds of smoke circulated geen e me a ng ae and 
escaped by the stopcock closing the ou The flame seen 
through this smoke is reddish and the x: is soul to a charred 
and much soot deposited, doubtless owing to the dissociation of 
Am. Jour Scr. THTRD ~~ IX, No. 58.—May, 1875. 
