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POPULAR SCIENCE REVIEW. 
who gave it, and in aid of the common cause of scientific learning in which 
the whole world takes an interest. This is an example worthy of imita- 
tion. The trustees who have charge of the Tyndall Fund will no doubt be 
glad to have the amount increased as largely as our wealthy citizens may 
desire. They cannot have too much money for the promotion of original 
research, and it is equally certain that no investigation foimded upon correct 
scientific reasoning can be made in vain.” 
Improvement in Safety Valves. — This consists of an arrangement of spring 
loaded safety-valves for marine boilers, designed by Messrs. PoUit and 
Wigzell, of Sowerby Bridge, and lately applied by them on board a steam- 
ship which they are fitting with engines. “ Engineering ” says that the 
valves are of the ordinary form, and are fitted with the usual lifting gear ; 
but on the top of the valve box are fixed two cylindrical casings, each con- 
taining a helical spring which bears upon a disk carried by the spindle of 
the corresponding valve. The lower ends of these spring casings are kept 
air and water tight by india-rubber disks, while at the upper end each 
casing is fitted with a cap secured by a bolt and padlock, this cap preventing 
the spring from being tampered with. The valves are quite free, and can be 
turned round by the two flat places formed on the spindles just above the 
valve box cover. The arrangement is a very simple one, and the plan of 
protecting the spring by means of an india-rubber disk, which closes the 
mouth of the spring case, and at the same time does not interfere with the 
play of the valve, is, we believe, novel. 
MEDICAL SCIENCE. 
Seat Produced in Body^ and Effects of Exposure to Cold. — This subject 
has been thoroughly investigated by Dr. Draper of New York, who com- 
municates a paper on the matter to Silliman’s American Journal ” for 
December, 1872. After giving the figures resulting from experiments in 
columns, he says that if we compare the column representing the con- 
dition before entering the bath with that representing the condition 
immediately after leaving it, we find that in both experiments the exposure 
for one hour to water at a temperature of about 74° F. lowered the tem- 
perature of the mouth two degrees, of the armpit four degrees, and of the 
temple two degrees. The rate of respiration is also diminished in one case 
two and in the other four movements, and that of the pulse twenty beats in 
one, and twenty-three in the other. It is therefore evident that the effect 
of the long continued application of a degree of cold such as that em- 
ployed is to reduce the temperature of the body and the rate of respiration 
slightly, while it affects the rate of pulsation in a very profound manner. 
One of the consequences of this effect of cold on the action of the heart 
was a great reduction in the quantity of oxygen introduced into the system. 
The rate of pulsation being reduced nearly one-third, the quantity of oxygen 
conveyed into the interior of the body was diminished in a somewhat similar 
ratio. In a short time this began to exert its influence on the nervous 
centres, and there was an overwhelming disposition to fall asleep, which was 
