Popular Science Monthly 



A Photographic Trick— Try It 

 the Night of the Fourth 



THE young man in 

 the accompanying 

 illustration, pictured as 

 looking so calmly and 

 critically at us from 

 behind one of the rings 

 of Saturn or some other 

 astronomical wonder, 

 is really standing out 

 in his own back yard, 

 in Hornell, New York, 

 and posing for his pho- 

 tograph while whirling 

 a sparkler, such as 

 children delight in for 

 the safe and sane 

 Fourth of July cele- 

 bration. 



A four by five camera 

 was used with a poly- 

 chrome plate. The 

 photograph was taken 

 by the light of the 

 sparkler, and the dark 

 spot over the right shoulder is the 

 which held and whirled it. 



the suitcase laboratory illustrated, with 

 which valuable information is quickly 

 obtained as to the purity of chemicals. 

 This "pocket edi- 

 tion" laboratory en- 

 ables the laundryman 

 to test all his materials 

 as he buys them. Thus 

 he is able to assure 

 himself that everything 

 used in his establish- 

 ment is of a sort that 

 will not damage or 

 harm the goods en- 

 trusted to him. In 

 other words, he sub- 

 mits all his purchases 

 to a chemical analysis, 

 without going to the 

 expense of hiring a 

 chemist to do the same 

 thing for him. 



When closed , the lab- 

 oratory resembles a 

 suitcase. It becomes a 

 laboratory by raising 

 the handle side and 

 lowering the side which forms the lid. The 

 lowered side forms a table. 



a photograph by the light 

 ng sparkler which he holds 



hand 



A Suitcase Laboratory for the 

 Use of the Laundryman 



THE Mellon Institute of Industrial 

 Research has been studying the laun- 

 dry business scientifically. It wants to 

 help the laundrymen guard against bad 

 laundrv materials. The result has been 



The suitcase labor- 

 atory which is used 

 by laundrymen for 

 testing the materi- 

 als they use and the 

 hardness of water 



A Hint to Motorists — Keep Your 

 Radiator Clean 



TO assure the efficient operation and 

 long life of your automobile, it is 

 essential that the radiator be kept clean. 

 Every radiator has been designed for the 

 purpose of dissipating some of the heat 

 from the engine to prevent it from over- 

 heating. The radiator can only accomplish 

 this when the radiator cells are cleared of 

 mud so that the comparatively cool 

 ^^^^ air can circulate through it. Yet 

 ^M 8L many are the cars which are 



^ PPtt allowed to clog up with 



mud and dirt until it al- 

 most takes a hammer 

 to knock it out. A 

 good antidote is a 

 powerful stream of 

 water from a hose; 

 or where this may 

 not be convenient, a 

 stiff brush or a broom 

 will assist in solving 

 the cleaning problem. 

 Care in this respect 

 will be repaid in good 

 measure. 



