Popular Science Monthly 



513 



In this holder the baby 

 sits when awake or lies 

 when asleep on the trip 



Can the Baby When You Take 

 a Journey 



THE good news is true. We have 

 been hoping for years that some in- 

 telligent inventor 

 would come along 

 with a device to 

 can obstreperous 

 infants during the 

 late hours of the 

 night. We sug- 

 gested a hermeti- 

 cally-sealed can 

 wrapped in 

 sound-proof ma- 

 terial, but Caleb 

 M. Prather, of 

 Evanston, 1 1 1 i - 

 nois, who is the 

 inventor of the 

 can illustrated, 

 sidestepped our 



instructions at several important points. 

 He intends to use the can to rock babies 

 to sleep. It is, in fact, a baby holder. Our 

 can was to be a baby holder and silencer 

 combined. Mr. Prather has provided sev- 

 eral holes in his can through which air can 

 reach the baby. We don't object to the 

 baby getting air but as long as there are 

 holes in the can the baby's yells will be 

 as nerve-wracking as ever. That was 

 our reason for the 

 hermetically-sealed 

 can. A cover of 

 the can is fastened 

 by a button, and a 

 seat is provided 

 upon which the 

 baby can sit and 

 suck his thumb 

 when the top and 

 cover have been re- 

 moved. The can is 

 of steel and it can 

 be fastened to the 

 rail of a porch, the 

 back of a chair, or 

 the seat of a rail- 

 road car. If the 

 inventor will make 

 his can air-tight 

 and sound-proof — 

 features which we 

 originally suggested 

 — we know of a 

 bachelor who will 

 buy a half dozen 

 right away. 



Shells filled witn water are subjected to a 

 strong water pressure test for thirty seconds 



Will the Shell Burst When It Is 

 Fired? A Water Test Tells 



A PROJECTILE fired from a gun is 

 subjected to enormous strains which it 

 must be strong 

 enough to with- 

 stand; otherwise 

 it might be as 

 dangerous to the 

 gun crew as to 

 the enemy. To 

 assure safety as 

 well as destruc- 

 tiveness, the steel 

 from which the 

 shells are made is 

 subjected to different 

 tests. Not only this 

 but further examination 

 is customarily made on 

 what are known as test 

 shells. Some of these 

 test shslls are actually fired in the testing 

 grounds; others are cut up and the pieces 

 subjected to various strains which must be 

 successfully resisted. 



Since this can't be done to every shell, the 

 shells used are picked at random, it being 

 assumed that they typify the lot. The 

 probabilities are that this would be so, but. 

 it is better to supply a simple pressure test 

 required for some of the French shells. 



This French pres- 

 sure test consists 

 simply of fillingeach 

 shell with water and 

 then subjecting it 

 to a strong water 

 pressure for about 

 thirty seconds. If 

 the shells are weak, 

 they will either 

 burst under the 

 strain or a per- 

 manent expansion 

 will take place. On 

 the other hand, if 

 the shells do not 

 collapse and no per- 

 manent expansion 

 takes place, the 

 shells must be satis- 

 factory so far as 

 their strength is 

 concerned. This is 

 conclusive evidence 

 which can be se- 

 cured for each shell 

 with little trouble. 



