NOTES AND ABSTRACTS IN CHEMISTRY AND PHARMACY. 
37 
recovered perfectly. Of the third five, one died; the four others suffered but 
slight indisposition. The two deaths may be accounted for by the fact that the 
animals happened to be among those operated upon on the 22nd of January, 
when the cold was extremely severe; added to which they received the largest 
dose of phosphorus (0'3 gramme) without any increase in the quantity of anti¬ 
dote. The influence of the extreme cold added to the depressing effect of the 
phosphorus may have led to the fatal result. 
M. Personne conceives that the turpentine acts by impeding or preventing the 
oxidation of the absorbed phosphorus at the expense of the oxygen of the blood, 
in the same way that it arrests the slow oxidation of phosphorus in the air. 
Influence of Pressure on Chemical Phenomena. 
M. L. Cailletet has published* some interesting experiments on the influence 
of pressure on chemical reactions. Thus he shows that the action of hydrochloric 
acid upon a sheet of zinc diminishes in exact proportions to the increase of at¬ 
mospheric pressure upon the substances, and may even be made to cease en¬ 
tirely. By weighing the sheet of zinc before and after the action of the liquid 
acid, the loss of metal is shown to be— 
When operating in open air.10*0 
„ „ at a pressure of 60 atmospheres . . 4-7 
„ „ „ . 120 „ . . OT 
and comparative experiments with nitric acid acting on a crystal of carbonate of 
lime, under a pressure of 150 atmospheres, and in the open air, the quantities 
of carbonate dissolved in an equal time are in the proportion of 1 to 11 09. 
It is also shown that the most energetic acids exercise scarcely any action on 
iron, tin, aluminium, or sulphide of iron, when submitted to high pressure. The 
decomposition of water by the galvanic pile is similarly influenced by increased 
pressure. A disengagement of gas in a voltameter, which is abundant in the 
open air, ceases completely when the atmospheric pressure is sufficiently aug¬ 
mented. By enclosing in a sealed tube an amalgam of sodium and some water, 
the oxidation of the sodium may be almost completely arrested in consequence 
of the pressure developed by the accumulation of the hydrogen in the limited 
space. On opening the tube after several days, the disengagement of gas again 
commences. The same quantity of amalgam in contact with water at the or¬ 
dinary atmospheric pressure loses all trace of it3 sodium in a very short time. 
Chemical action thus largely reduced by pressure, can acquire new activity 
by an elevation of temperature. Thus the quantities of zinc dissolved by diluted 
sulphuric acid at zero, and in a tube heated to 50° C. are in the proportion of 
1 to 2‘8. These facts seem to completely assimilate the disengagement of gas 
by chemical action to the ebullition of liquids. 
The foregoing experiments having demonstrated that the chemical action 
diminished in proportion to the increase of pressure, M. Cailletet sought to 
ascertain whether the same phenomena of decomposition would be augmented 
in intensity by the removal of the ordinary atmospheric pressure; that is to say, 
by operating in a vacuum. He found that the quantities of aluminium dissolved 
in hydrochloric acid in equal times in the free air and in a vacuum were in the 
proportion of 1 to 1*68; of zinc in sulphuric acid, 1 to 1*53 ; and of carbonate 
of lime in nitric acid, 1 to 2*51. He concludes, therefore, that pressure exer¬ 
cises an important influence on chemical phenomena, that the evolution of gas 
by chemical decomposition is subject to the same physical control as the ebul¬ 
lition of liquids, and that chemical changes may therefore be as much attri¬ 
butable to the mechanical conditions under which they occur, as to the opera¬ 
tion of any particular force of affinity. 
* ‘ Journal de Pharmacie,’ 1869. 
