PIRINQ POINTS OF VARIOUS EXPLOSIVES.
57
too much nitrous ether was formed and, in the case of benzoi'c acid, benzoi'c ether in addition. Substitution products formed in these reactions. The benzoi'c acid, treated with carbon disnlphide and nitrous anhydride, without using alcohol as a solvent, furnished a nitroso compound, the barium salt of which was prepared after we had carefully driven off the unattacked benzoi'c acid by persistent boiling, continued for nearly a week, replacing the water a t intervals. The acid, separated from its barium salt by means of sulphuric acid, melted a t 1 1 4 O C. The barium salt is very sparingly soluble in alcohol, but easily in water, yielding an amber-yellow solution from which the salt crystallized in a few days. A barium determination, using 0.1949 grm. of the crystals, was made, and 0.0953 grm. barium sulphate were obtained. Theory demands 28.98 per cent. Ba for barium i~itrosobenzoate of the formula (C,H,. ?TO. COO),. Be 2H,O.
+
We found, according to the figures given : 28.73 per cent. We have thus found a direct way of preparing nitroso acids, a t least nitrosobenzoi'c acid, which we shall now try to obtain in larger quantities, using sealed tubes, if possible, for the reaction. The alcoholic solution of phthalic acid, when acted upon by nitrous anhydride, furnished a yellow oil which solidified after several weeks. It could not yet be used for any determination. COLLEGE OF THE CITY OF
NEW YORK,
March 7 , 1890.
DETERMINATIONS O F THE F I R I N G POINTS OF VARIOUS EXPLOSIVES.
BY CHARLES E. MKNROE. For this purpose an apparatus devised by Mr. Horsley,* was used which consisted of an iron stand with a ring support holding a hemispherical iron vessel in which paraffine or tin was put. *Trans. SOC.Eng. (Eng.)1872,page 15.
58
FIRING POINTS OF VARIOUS EXPLOSIT'ES.
Above this was another movable support from which a tliermometer was suspended and so adjusted that its bulb was immersed in molten material in the iron vessel. A thin copper cartridge case, 4 inch in diameter and 1& inches 10119., wits suspended over the bath by means of a triangle so that tlie end of thecase was one inch below the surface of the liquid. O n beginning the experiment the material i n the bath was heated to just above the melting point, the thermometer was iiiserted in it and a minute quantity of the explosive was placed in thc bottom of the cartridge case. The temperature marked by the thermometer was noted as the initial ternyernfuw, tlic cartridgc o:ise containing tlie explosive was inserted in the bath and tlic tempcrature quic,klp raised until the explosive flashed off or exploded, when the temperature marked by the thermometer was agai11,notedits the jii-iiLg poimtt. The following tables contain the results thus obtained : (IUIU-('OTTON.
Initial temp. 65" 65" 80" 90" 125"
c. i t ('
(i
64
Firing point. 192" c. 201" ( r 198" (' 18Gc '( 199" "
Iuitinl tamnp.
'
129'
c.
148"
"
15(jr,
L I
158"
(I
E'iriiig point. "OOO c'. .700" 199' ]99"
i( tl i t
I
This was freshly macle, compressed military gun-cotton and i t was made with standard acids, viz., a mixture of three parts of H,SO, Sp. gr. 1.845, and one part of HXO, Sp. gr. 1.5. One centigrm. of the material was used in each of the gun-cotton experiments. A I R - D R I E D GUN-COTTON.
Initiai temp.
Firing point. 1 ImLitiaZ temp. 1 8 2 O c. 170" 0.
100"
c.
116"
(L
IT3"
66
170"
"
1850
il
~
170" " 170" ( i
Firing point. 186" C. 18;"
4 . 10: 175- (' 135" " 17'3" I 170 - * 1s1 " This fulminate was recently made. It was wholly free from metallic mercury and was in microscopic crystals of very uniform size. The crystals were beautifully twiiined and reticulated and belonged apparently to the orthorhonibic SJ stem. * L
Initial temp. 242" c. 250" '( "5y"
((
261"
((
lnitinl te))ip. 262" c. 269" '. 269" (' 270" "
Initiul t e n q . 238" c.
239" '( 240" '' 244" ' 6
63
F I R I N G POINTS OF VARIOUS EXPLOSIVES.
These powders had been in store about ten years and they were composed of : 42.18 Ammonium picrate 53.79 Potassium nitrate 3.85 Charcoal
lititial temp. 60" C.
Firing point. 185" C. 190° '( 188" ' I 190" (' 200" ('
80" '( 90" 100" 6 6 110" "
'(
Initial temp. 50" C. 80" 100" (< 120" 130" (' ((
Initial temp. 60" C.
io
r o cc
80" 90" 100"
r(
(' ((
60" C. 70" ( < 90" " 100" " 120" "
Firing point. 175" C. 178" '( 176" 176" 184" '' ((
Firing point. 178" C. 184" '
