Page 



A Machine for Cleaning Ceilings 84 1 



An Unusually Intelligent Slot Machine 842 



Mechanical Kinks 876—877 



The Giant Destroyer of the Future 897 



MEDICINE, SURGERY AND HYGIENE 



What X-Rayg Can Do for Your Teeth 20 



Killing Vermin with Gas 119 



Modern Methods for Exterminating the Mosquito 166 



Soldier of Today Better Off Amid New Horrors. . . 184 



Eradication of Weeds Will Prevent Hay-Fever. . , 238 



How to Get Thin and Fool the Family 240 



Chinese Doctors and Their Ways 243 



War Will Diminish Stature and Vigor of Human 



Race 252 



If Your Hand Is Too Small— Stretch It 361 



Exterminating Mosquitoes 367 



The Latest Answer to "What Is a Cold?" 374 



Fighting Infantile Paralysis 399 



Taking a Census of Occupational Diseases 486 



A Mechanical Masseur That Works Off Fat 486 



Have You Perchance a "Vocational Disease?" ... 519 



Where Beautiful Hair Is Not a Crowning Glory. . 528 

 Eliminating One of the Tortures of the Dentist's 



Chair 534 



How Do You Sit? 551 



Sampling the Drinks for an Entire Large City . . 556 



Steam Yourself and Drive Away Your Ills 575 



Testing the Air-Fighter's Nerve 580 



Mechaoical Lungs for the Fire-Fighter 587 



Some Peculiarities of Eye-Glasses 616 



More Light on the Occupant of the Dentist's Chair 626 



A Simple Electrical Device for Purifying Water. . 638 



Measuring the Horsepower of That Baby of Yours 644 



Exercising Machines for Wounded Soldiers 633 



A Humane Method of Destroying Horses 684 



New Apparatus for Setting Broken Limbs 684 



Using the X-Ray on Animals 696 



Defense for the Ears Against Noise and Shock. . . 707 



Resuscitating the Drowned 744 



Lifting Invalids with a Minimum of Discomfort. . 746 



Why Do We Grow Bald? 812 



New Cures at the Royal Baths in England 818 



Making Air Fit to Breathe 833 



Medicinal Cartridge-Beit for Peaceful Expeditions 849 

 A Device Invented by a Blind Doctor to Enable 



Himself to Write Letters 849 



Humanity's Bent Twigs 850 



Corns — What They Are and Why They Hurt. . . . 857 



The Medicinal and Hygienic Virtues of the Lemon 863 



The Cancer Problem 873 



Friction Tape Used for Plaster Strips 925 



MINING 



Steaming Frozen Ground for Gold 687 



Coal-Mine Fatalities in the United States During 



the Year 1915 696 



NATURAL SCIENCE 



How Fish Jump 1 00-Foot Dams 364 



Borrowing the Night Lamps of the Fireflies 365 



Why Whiskers Continue to Be in Style for Cats. . 369 



Fishing in Guiana with the Bow and Arrow 385 



When Manicuring Nails Is a Dangerous Job 410 



Rocking Stones and Their Romantic Story 413 



Even the Hornets Have New Ideas Sometimes, . . 417 

 Exploiting the Island of Laysan for the Eggs of the 



Albatross 428-429 



The Reason Why We Have Two Eyes 434 



Insect Grotesques 496-497 



When Nature Plays the Architect 498-499 



Freak Trees. How Did They Happen? . 512 



A Curious Egg Shaped Like a Dumb-Bell 513 



A Slab of Sandstone Seventy-Five Million Years 



Old /. 513 



Would You Recognize the Ear-Bone of a Whale If 



You Saw One? 513 



Why the Color of Sen Water Is Blue or Green. . . 522 



Crossing Dangerous Rivers with Goatskin Floats . 528 



A Mat^ician Among the FishcB 562 



The Strange Vegetable Sheep of Peru 563 



Why You Hear Well on a Clear. Frosty Night . 646 

 Weather Bureau Duties Overlooked in Criticising 



the Weather Prophet 647 



The Tree Warfare Against Rocks 650 



The Traveler's Tree 651 



A Fish That Builds a Nest Like a Bird , 654 



Page 



The Great Hoodoo Temple 655 



When Rain, Thunder and Lightning Start Toward 



the Earth at the Same Time 674 



The Deepest Known Place in the Ocean 683 



Nature and Not Cannons the Cause of Rainfall. . , 744 



Queer Denizens of the Deep 822 



Is This the Origin of Forcible Feeding? 823 



As a Packer Let Us Recommend Mother Nature . . 826 



Not Candy but Moth and Butterfly Eggs 827 



Iridescent Fish-Eggs for Table Decoration 875 



"Great Fleas Have Little Fleas Upon Their Backs 



to Bite 'Em " 875 



Why Does Sap Rise Against Gravity? 886 



PHOTOGRAPHY AND MOTION-PICTURES 



As Easily Handled as a Rifle , 77 



Seeing the Unseen 89 



Photography in Natural Colors 102 



A Dark-Room Lamp I 20 



How to Photograph Wild Animals. 136 



Catastrophes by the Foot 163 



Comic Insect Photography 191 



A Photographic Eye for the Airman 202 



Washington Monument as a Motion-Picture Screen 354 



Staging the Celluloid Thriller 401 



An X-Ray Tilting Table 407 



"Shooting" a Photograph with a Pistol-Camera 408 



Pendulum for the Dark Room 4bO 



An Improvised Reflecting-Camera 460 



Novel Device for Copying Pictures 460 



Home-Made Camera Shutter 461 



A Useful Trimming Board 461 



Simple Test of Shutter Speed 461 



Cheap Photographic Changing Box 473 



Wild Animals That Photograph Themselves 483 



Preserving the Orchestra Leader's Art 535 



Drying Negatives by Heat from a Kerosene Lamp 602 

 A Photographic Printing-Box for Use with Electric 



Current 603 



Saving the Picture Show with a New Rheostat . . . 633 



Using the X-Ray on Animals 696 



A Daylight Developing-Tank . 716 



Boring Straight by Photography 720 



Making the Music Fit the Movie 733 



"Shooting" Birds with a Camera ' 741 



Eight Pictures on One Plate 856 



Photographic Printing Masks Easily Made 931 



A Dark-Room Lamp to Be Used Under a Glass 



Tray 934 



PICTURE PAGES 



A Tree Like the Rock Which Moses Smote 651 



Exercising Machines for Wounded Soldiers 653 



A Fish that Builds a Nest Like a Bird 654 



The Great Hoodoo Temple 655 



Where Germany Gets Her Basalt Paving Blocks. . 656 



Relics of Indian Superstition 658 



Curious Clocks of Paris 659 



A Great Collapsible Field Periscope 660 



Watching a Battle Through a Super-Periscope. . . 661 



The Largest Duck Farm in the World 662-663 



Let a Puff of Air Do It 664 



Air Is Stronger Than Human Arms 665 



A Modern "Newspaper Maker" 676 



Using the Telephone on the Rifle Range 682 



Scenes in Alaska 814 — 815 



Marooned by the Tide at West Australia 816 



Trapshooting in the Navy 817 



New Cures at the Royal Baths in England 8l8 



Tropical "Snow Drifts" of Cheesecloth 819 



Food Freaks 820—82 I 



Queer Denizens of the Deep 822 



Is This the Origin of Forcible Feeding? 823 



Fighting Weapons of Seven Warring Powers.... 824 



Aeroplane Art of To-day 825 



As a Packer Let Us Recommend Mother Nature. . 826 



Not Candy but Moth and Butterfly Eggs 827 



Japanese Ivory Carvers Use Modern Tools 828 



PRACTICAL WORKERS DEPARTMENT 



How to Make an Efficient Boiler-Patch 117 



An Easily Made Mercurial Barometer I 18 



A Handy One-Drop Oiler I 20 



A Non-Spillable Funnel 120 



Rubbing in the Lathe 120 



An All-Steel Screwdriver 121 



A Buck-Saw Attachment 121 



