170 
THE TREATMENT OF CHOLERA. 
in London has the value of 100, would be but 91 at Munich, and only Gl‘5 in Mexico. 
Indeed, the difference would be greater than this, for not only is the light actually less 
for equal consumptions, but as the volume of the gas expands with the rarefaction and 
temperature, the real value of the same quality of gas as measured by the meter in 
Mexico would be only 46‘2. Even in London the difference in the value of the light 
when the barometer is 31 as compared with what it is at 28 is fully 25 per dent.; and it 
may well be that this difference is noticeable. 
If the rarefaction of the gas and air are carried to a very great extent they cease to 
burn. The flame of coal-gas, as well as that of a candle and of spirit of wine and ether, 
is extinguished at a rarefaction of about l-6th of the atmosphere; hydrogen, at l-7th j 
sulphur, at l-15th; and phosphorus, at l-60th. On the contrary, if the atmospheric 
pressure is increased, the luminosity of a flame is also increased, and it would seem that 
up to considerable pressures the rate of increase is in the observed proportion of 5T per 
cent, for every inch of mercurial pressure; and by doubling the atmospheric pressure the 
light of a gas-flame rises from 100 to 252. So marked is this on the luminosity of flame, 
that it is not difficult to make a spirit-lamp glow like a candle, or even to make it smoke. 
And then there is another circumstance which influences the light of a flame, namely, 
the temperature at which the combustion is going on. If the temperature is lowered, 
the light is also proportionally diminished. This is noticed in the flame of a candle 
which requires snuffing, when the charred wdck and the head of sooty carbon radiates the 
heat and lowers the temperature of the flame. But if by any means the temperature is in¬ 
creased, an opposite effect is produced. I have here a contrivance which was originally 
designed by Mr. Bowditch, and which has been somewhat modified by Dr. Frankland. 
It is a common Argand burner and glass, with another glass around it; and it is so 
arranged that all the air which supplies the burner must pass down between the glasses 
and be heated before it reaches the flame. The temperature which it thus acquires is 
from 500° to 600° Fahrenheit, and it passes to the flame as a sort of hot blast. The 
result of it is that the light for the same volume of gas is increased about 67 per cent, 
and for equal lights it is found that there is a saving of 46 per cent, of gas. 
Illuminating PowiT ivith and without the external Class in Sperm Candles of 120. 
Consumption 
per Hour. 
Cubic Feet. 
3‘3 
3-7 .. . 
Illuminating 
Power 
wthout Glass 
13*0 
15*5 
Illuminating 
Power 
with Glass. 
. 13-0 
. 15*5 
. 21-7 
These are the results v ith cannel gas, but I do not find there is a like increase of power 
with common gas. 
(To he continued^ 
THE TEEATMENT OF CHOLEKA. 
The Lords of her Majesty’s Privy Council having by their medical oflScer, Mr. Simon, 
addressed a letter to the College of Physicians relating to the expediency of issuing in¬ 
structions to captains of merchant vessels “ how they should act when proper medical 
attendance cannot be procured, so as to provide for the health of their crews against 
attacks of cholera,” the following is the substance of the reply forwarded by the 
College:— 
“ Their lordships request to be informed ‘ whether, in the opinion of the College, any, 
and if so, what suggestions might be issued as representing the present state of medical 
knowledge and experience with regard to the drugs which should be given, or other 
treatment which should be adopted, in attacks of cholera, and especially in the begin¬ 
ning of the disease, when proper medical attendance cannot be procured.’ Their lord- 
ships, at the same time, submit to the College a copy of the instructions issued on pre¬ 
vious occasions. 
“ With reference to that part of the instructions on which their lordships particularly 
