910 



Popular Science Monthfy 



the salts on top by passing up through 

 the porous substance from the magne- 

 sium chlorid below. In this way a good 

 sliding surface is maintained. 



Limbering the Muscles of 

 Fire-Fighters 



THAT the fireman's life is not all 

 velvet was proved in New Or- 

 leans recently, when the fire depart- 

 ment turned out in force and did 

 some remarkable feats of quick lad- 

 der-climbing for the edification of 

 the public. A tall wooden tower was 

 erected, ladders were hoisted into 

 position, and up these the firemen 

 climbed in record-breaking time. 

 The fire chief was so pleased with 

 the demonstration that he ordered the 

 tower to remain in its original position, 

 to be used in the future for regular 

 ladder-climbing exercise. 



In New York, where there is a fire 

 college connected with Central Head- 

 quarters to which firemen from all parts 

 of the world come to be enlightened in 

 the latest methods of combating blazes, 

 ladder-climbing forms one of the most 

 rigid courses of training. All sizes of 

 ladders are put up against the rear wall 

 of the college and up these the "rookies" 

 or probationary firemen are ordered by 

 their superiors. At the topmost point 

 of the highest ladder the rookies are 

 sometimes sent with scaling ladders, 

 which they attach to stone outcroppings 

 or window sills and go up fifty or sixty 

 feet further. This is the kind of training 

 which instills a spirit of daring in the 

 men. The training is made to resemble, 

 as closely as possible, the problems in- 

 volved in the actual work of fire-fighting. 



tmw* 



One Reason for Appreciating the 

 Value of Birds 



THE fecundity of certain insect forms 

 is astounding. The progeny of one 

 little insect, the "hopaphis," sees thirteen 

 generations born to it in a single year, 

 and would, if unchecked to the end of 

 the twelfth generation, multiply to the 

 inconceivable number of ten sex- 

 tillions of individuals. If this 

 brood were marshaled in line, ten 

 to the inch, it 

 would extend 

 to a point so 

 sunk in the 

 profundity of 

 space that 

 light from the 

 head of the 

 procession , 

 traveling at 

 the rate of one 

 hundred and 

 eighty-four 

 thousand 

 miles a sec- 

 ond, would 

 take two 

 thousand 

 five hundred 

 >^ e a r s to 

 reach the 

 earth. 



In eight 

 years the 

 progeny of 

 one pair of 

 gypsy moths 

 could destroy 

 all the foli- 

 age in the 

 United 

 States, if un- 

 checked. 



A demonstration of firemen's ability in ladder-climbing in New Orleans, La. These men 

 proved so efficient in practical life-saving methods, that their chief ordered the tower to be 

 left in position for the drilling of recruits 



