Popular Science Monthly 



69 



The sawing machine is pulled along at a leisurely rate, the saw cutting the ice in any direction 

 desired. The illustration at right above shows the old method of sawing the ice by hand 



It Bites Its Way Through the 

 Thickest Ice 



THE natives about a small lake in Iowa 

 were stupefied when ice-cutting time 

 came around to see what appeared to be a 

 motor sled, similar to the ones they had 

 seen pictured in the magazines, slide out 

 over the glazed surface of the frozen lake, 

 sink what appeared to be a large driving 

 wheel into the ice, and emit a loud scream. 

 This contrivance was not a motor sled, 



H 



RACK 



ENDLESS CHAIN 



DRIVE 

 PULLEY 



FRONT SLr 



The saw can be raised or lowered so as to 

 be accurately set at the proper elevation 



but a brand new type of ice-cutting 

 machine, equipped with a gasoline motor, 

 and the scream that made them look to 

 their life preservers, was the shrill sound 

 of the whirring saw as it bit into the ice. 

 When they went out and looked the 

 machine over they found, as intimated, a 

 squat, rigid sled upon the deck of which a 

 lusty one-cylinder gasoline engine was 

 bolted. A belt communicated the power 

 to a circular saw located aft, which was 

 driven at amazing speed. 



The inventor, who is John Hill, of Story 

 City, Iowa, demonstrated the machine, 

 showing that it could rip a straight line 

 through the ice at a speed which made the 

 ordinary up-and-down sawing method 

 seem to stand still. By a simple arrange- 

 ment the saw could be lifted off the ice or 

 lowered upon it with little effort. 



How Do Fish Locate Fresh-Water 

 So Unerringly? 



OW salt-water fishes determine where 

 they are, and why fresh-water fishes 

 can always find their way into rivers is 

 made clear by Drs. V. E. Shelford and E. B. 

 Powers, Their studies on the resistance 

 of salt-water fishes to the decayed and de- 

 composed things, lead to an explanation 

 of their habits. 



It appears that herrings can sense dif- 

 ferences in heat and cold as 

 small as a quarter of a degree or 

 less. They appreciate the fact 

 that only a trace of an acid or 

 alkali is present in water. So 

 sensitive are herring to acids and 

 alkalis that the scientists pro- 

 pose that these and other fish be 

 used to detect the chemicals in- 

 stead of the litmus paper, which 

 chemists use, and in the same 

 manner that canary birds are 

 used to discover traces of poison coal gas 

 in mines and elsewhere. 



In connection with the entrance of salmon 

 into rivers and other bodies of water, Drs. 

 Shelford and Powers say it is evident that 

 they find their way by virtue of the presence 

 or absence of acids and alkalis. 



Fish determine the direction they must 

 go to fresh water even when hundreds of 

 miles out at sea and find their way to bays, 

 harbors, and inlets when their mating 

 season demands it, by the chemical condi- 

 tions of the water. It is not necessary to 

 appeal to "instinct" to explain the return 

 of certain salmon to certain rivers or the 

 running of herrings in certain localities. 

 These new chemical discoveries make it 

 all clear that smell and touch are the senses 

 most concerned, and these are highly de- 

 veloped in certain species. 



