PopuJar Science Monthly
��A Field Refrigerator for the Camper or Soldier
THE illustration shows a very ingenious method adopted by a company in the war zone lor storing their food su|>plies, to keep them cool and out of the reach of the prowling dogs. A large stitutes the refriger- ator, which has been thoroughly cleaned of all rot. Shehes were set in and a hinged door of wire mesh fastened o\er the opening. In this case a steel door is used, but the camp- er can provide one of slats or poles that will serve his pur- pose as well.
Boy scouts will find the idea attrac- tive. The refrigera- tor might be located in some fa\'ored spot in which an old tree covered with iv\' would be available. This would elTectu- ally conceal the door from tramps or med- dlesome marauders.
���i^ Ceutial News
To protect edibles from wild dogs which infest the district this food safe was con- structed in the hollow of an old maple tree
��district. The accompanying photograph shows an adaptation of the caterpillar wheel — the caterpillar tread — attached to an English delivery cart.
Evidently the oc<ui)ants of the cater- pillar cart are agriculliual people who live in an oLitlying district where intermittent rains and hea\y traf- fic have played havoc \vith roads. By re- placing the wagon wheels of the cart with the tread the worst roads can be tra\eled over with comparative ease. 1 he principal draw- back is that tra\el with the caterpillar tread is slow. On the other hand, the horse sinks just as deep in the mud as he always did. If the vehicle were mo- tor-driven it would meet all require- ments. The only other alternative is tor some inventor to find an application of the caterpillar tread for horseshoes.
��A Caterpillar-Tread Cart for Conquering Bad Roads
CATERPILLAR wheels are generally associated with motor-driven appara- tus of great weight, such as huge tractors, trench diggers, army motor-truck trans- ports and, of recent exploitation, the "tanks" used by the British in their advance against the Germans in the Somme
���ig)Ibt. Film Scr%-
A caterpillar tread attached to an English delivery cart enables it to go anywhere regardless of the condition of the roads
��Shooting Soot From Stacks With Blasting Powder
WHEN powder-plant stacks accumulate enough soot to hinder the draft they can be cleaned by "shooting the stack" with a gun made for the purpose. This is nothing more than a wooden cannon, made of a piece of shafting fourteen inches long. One hole is bored into the center of the piece and a horizontal hole is bored through the piece to the bottom of the cen- ter bore. This completes the cannon.
Blasting powder is placed in the mouth of the cannon to about two inches from the top. This is tamped tothecollarwith dry clay, and a short fuse is inserted in the touch- hole. The cannon is placed at the bottom of the flue and the fuse is lit.