THE RAT PROBLEM. 
bolting from the runs, the co-operation of a dog is desirable. For the 
destruction of rats on board ship, the method just described may be 
strongly recommended; and, no matter whether employed on land or 
ship, the fact that sulphur dioxide gas is a disinfectant as well as a 
deodorant may be considered an advantage. For rat destruction on 
board ship, sulphur candles have been employed with success by the Port 
of London Authority. Probably the most successful means at our dis- 
posal for using sulphur dioxide gas is an apparatus manufactured by the 
Clayton Fire Extinguishing and Disinfecting Company Limited, Lon- 
don. ‘The Clayton machine is provided with a generator, in which the 
gas is made and driven through a hose by means of a powerful blower. 
Two other bodies may be employed for causing rats to leave their 
runs when hunting along hedgerows or in old farm buildings where the 
runs are within thick walls :— 
Carbon disulphide is a colourless, heavy, and extremely volatile liquid. 
It may be employed by soaking wadding, cotton waste, or some such 
material and placing the latter into the hole and then immediately cover- 
ing the hole in. Jn this way the vapour is allowed to permeate the 
runs. As the vapour of carbon disulphide is highly poisonous, it must 
be used with caution, and no light or smoking should be allowed during 
its application. 
Acetylene is a colourless, rather heavy gas, having a peculiar, un- 
pleasant odour. It is made by decomposing calcium carbide with the 
aid of water. When employed along hedgerows, pieces of calcium car- 
bide within tow may be placed within the entrance of the run, then, 
after saturating with water, the entrance is quickly closed in with 
pieces of turf. Owing to acetylene being not only highly poisonous, but 
exceedingly explosive, great care must be exercised as to its application, 
which should not be within buildings. 
TRaAPPrINa. 
There are numerous kinds of cage and other traps on the market, 
most of which are more or less successful. Probably the most successful 
type is the Brailsford Trap. It consists of a long narrow wire cage, 
with doors at each end, which, when the trap is set, remain open, having 
a direct passage through. A platform in the centre, where the bait is 
placed, is connected by a spring, which, when trodden upon, releases 
the doors, imprisoning the rat or rats. It has been found that the trap 
8 inches high gives by far the best results. 
The Mysto Trap consists of a metal structure connected with a tank 
full of water. The bait is placed just inside the door, which closes on 
the entry of the rat. In order to effect its escape, the rat climbs up the 
cage to a hinged platform, which collapses; precipitating the rodent into 
the tank. The collapse of this platform automatically opens the door of 
the cage, and the next rat is thus enabled to enter and repeat the 
performance. 
Barrel Trap—This may consist of a barrel, the upper and open 
part being covered with brown paper, which is cut crosswise over the 
middle. The bait is suspended by a thin wire immediately over the 
centre or where the cuts intersect. The rat, in attempting to reach the 
bait, is suddenly precipitated into the barrel. 
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