256 



LAWRENCE HARGRAYE. 



COMPARISON OF PLYING MACHINES. 





Total 



Square 

 inches 



-22 



Power 

 used, 



foot- 

 pouuds. 



Distance 



Observations made with. 



area, 

 aqua re 



inches. 



area per 

 pound 

 weight. 



t 1 ^ 



tiown, 

 feet. 



• 

 24 Band A. 



1236 



841 



1-47 



164 



120 



„ B 



1381 



1132 



1-22 



197 



170 



„ c 



1177 



997 



1-18 



246 



201 



48 Band} J/ 



1606 



873 



1-84 



371 



189 



1551 



843 



1-84 



341 



171 



(■£;.'" .:: '.'.'. '.'. 



1986 



1555 



1-28 



193 



192 



24 Band ] J 



1974 



1542 



1-28 



208 



203 



(k 



1974 



1542 



1-28 



218 



209 



| 48 Band L 



2130 



1019 



2-09 



•470 



270 



48 Band — Screw 



2090 



1045 



2-00 



196 



120 



40*5 oz. — Compressed Air ... 



2344 



925 



253 



3000 



368 



74 oz. — Compressed Air 



4266 



922 



4-63 



2720 



343 



Cross bow model P. ... 



216 



1384 



•156 



7-5 



18 



Cross bow model C. ... 



. 756 



1862 



•406 



75 



20 



The air pump shown to the left in the photograph exhibited is 

 new ; it has a cylinder 2 inches in diameter and 8 inches stroke. 

 With this one the receivers can be pressed to 150 lbs. per square 

 inch with one hand ; with both hands a receiver can be charged 

 to 250 lbs. per square inch. The bottom of the cylinder gets 

 uncomfortably hot, so that the tin thing you see on the top of the 

 pump was made to convey some of the heat away to the water in 

 it. It will be advantageous to turn the pump the other way up 

 so that it can stand altogether in a vessel of water, the handle 

 will then have to be bent instead of straight. 



