110 



THE WORLD'S ADVANCE for JULY 



Electrical Testing Laboratories, Inc. 



Electrical Department 



Tests and investigations of electrical instruments, apparatus and materials. Inspec- 

 tion of electrical material and apparatus at factories. Tests and investigations 

 made anywhere. 



Photometrical Department 



Photometrical tests of all forms of commercial illuminants. Illumination tests 

 made anywhere indoors or outdoors. 



General Testing Department 



Mechanical tests. Chemical tests. Coal and ash analyzed. Paper tested. Tensile, 

 compression and torsion tests of structural and engineering materials. 



80th Street and East End Avenue 



NEW YORK, N. Y. 





The 



Line 



LEADS 



Newly -devised 

 patented feat- 

 ures on coils 

 and I iber a I 

 guarantees 

 on batteries 

 are its recom- 

 mendation. 



Handled by 

 all representa- 

 tive dealers. 



Send for replete catalog 



Interstate Electric Novelty Co. 



29-31 Park Place, New York 



Chicago San Francisco Toronto, Canada 



A NEW INVENTION FOR SEEING THROUGH 

 WALLS 



Just before sailing to Italy recently, Guglielmo Mar- 

 coni, the inventor of wireless telegraphy made the 

 interesting announcement that he is working on an 

 invention that permits persons to see through walls. 

 "I have not quite perfected it," Marconi said. "Per- 

 sons can be seen in the next room if they are close 

 enough to the wall, but at any distance they become 

 blurred. The transparency effected is not complete 

 yet, but so far as I have progressed with it the idea 

 is rather attractive." 



Inc 

 I AC 



Xi w; 

 "^sn 



UNIQUE FOUNTAIN PEN LIGHT 



Indispensable to Photographers and Motorcyclists 



An Ornament Neat and Compact 

 AGENTS STRONG BATTERY LAMP p O8 t 



^IJL WELL FINISHED HARD 

 WANTED RUBBER CASE COMPLETE 



SMITH NOVELTY CO. 



II | 



lists 







stpaid . 



TSc X 



POWER 



for YOU! 



4 



ILindstrom-Smith Co. 



Power from within! Strength 

 that is more than mere mus- 

 cular strength the strength of perfect health 

 now within yovrr reach through Vibration! 

 ALL THE JOYS OF YOUTH 

 may be yours through a White Cross Elec- 

 tric Vibrator. Vibration .is life itself. It 

 will chase away the years like magic. Every 

 nerve, every fibre in your whole body will fair- 

 ly tingle with the force of your own awakened 

 power. You're made over new from head 

 M/jk to foot. 



"^ Send a Postal for Our Big Book! 

 put your name and address on a postal and 

 mail it to us today. We will send you our splen- 

 did big FREE book telling you all about the marvels 

 of the White Cross Electrie Vibrator. Read what scien- 

 tistssay about it. Post yourself on what it will do for you. 

 Learn all about the White Cross EleotrieTibrator and our 

 limited offer. You are under no obligations whatever. 

 1100 So. 

 Dept. B14 



DO YOU KNOW 



What "cellular massage" means 1 



There is a big difference between m- 

 chanical and "cellular massage." Get 

 a description of our VIOLETTA-RAY- 

 GENE11ATOR, a wonderful new instru- 

 ment. It helps where drugs need help. 

 It gives strength and health by means 

 of HIGH-FREQUENCY current. All 

 details free. Indorsed by thousands of 

 physicians throughout the country. 

 Bleadon-Dunn Co., 210 N. 5th Ave., Chicago/Ill. 



FREE 



80 PAGE BOOK ON 



VIBRATORY MASSAGE 



Send for it at once and learn how you can 

 regain health and strength by Vibratory Massage 

 with Arnold Massage Vibrator and all details of 

 our FREE Trial Offer. 

 ARNOLD ELECTRIC CO. 



BOIL EGGS OR WARM LIQUIDS 



The Hold-Heet Immersion Heater is the 

 handiest, most economical device for heating 

 liquids. A great convenience at the dining table. 

 Heats in one minute boils in three minutes. A 

 necessity for the sick room and nursery. Packed 

 in neat leatherette case. As easy to use as a 

 teaspoon. Price $3.00. Write for free booklet on 

 practical electrical home conveniences. 



NATIONAL ELECTRIC CO. 

 546 West Austin Ave., Dept. 545 S. Chicago. III. 



Chapco Scientific Instruments 



are sold direct at Rock Bottom Prices 



Chapco Scientific Instruments, apparatus, material and supplies 

 for the scientist, instructor, experimenter, chemist, agricul- 

 turist, botanist and physicist are used and endorsed by the 

 Science Departments of thousands of American Schools, Col- 

 leges and Universities. 



Illustrated catalog free on request no obligation Write for 



your copy TODAY. 

 CHICAGO APPARATUS CO., 36 S. Clinton St.. CHICAGO, ILL. 



For our Mutual Advantage mention The World's Advance when writing to advertisers. 



