908 



Popular Science Monthly 



In 1 90 1, for example, there appeared the 

 brilHant new star Nova Persei. Long 

 exposure photographs showed that the 

 star was enveloped by an extensive and 

 beautiful nebula. That was in itself 

 not remarkable. But a second exposure 

 made several 

 weeks later 

 showed that the 

 shape of the 

 nebula had 

 changed and 

 that it had ex- 

 panded out- 

 ward. Astrono- 

 mers were be- 

 wildered. The 

 star is so very 

 distant from us 

 that it takes its 

 light centuries 

 to reach us. We 

 saw it on the 

 plates, not as it 

 appeared when 

 the exposures 

 were made, but 

 as it appeared 

 long before the 

 steam engine 

 was invented, 

 long before 

 there were rail- 

 roads. Obvious- 

 ly, the real dis- 

 tance in miles 

 traveled by this 

 expanding por- 

 tion of the neb- 

 ula must have 

 been enormous. 

 Attempt after 

 attempt was 

 made to explain 

 this apparently 



incredible phenomenon ; but nothing really 

 satisfactory has yet been suggested. 



Far less dramatic, but of immense value, 

 is the photographic work done at Harvard 

 in mapping the sky. The map is not made 

 once for all, but its separate sections are 

 constantly rephotographed. The plates 

 are stored in a fireproof building erected 

 especially for the purpose. With such a 

 photographic record, it becomes possible 

 to study the past history of a star at any 

 time. The study of these photographs 

 constitutes a very important part of the 

 work, which is done mostly by women. 



Freighting a Steamer by Means of a 

 Marine Elevator 



A 



The platform of the elevator is brought to the level of 

 the dock where it is quickly loaded. An electric 

 motor then hoists it to the deck of the steamer 



vessel to be loaded at any time or tide, 

 which doubles the normal rate of the load- 

 ing and which re- 

 duces expenses 

 a corresponding 

 amount is now 

 being intro- 

 duced all along 

 our coasts. For- 

 merly a coast 

 steamer had tx> 

 wait for the tide 

 to come in be- 

 fore she could 

 steam up to the 

 loading dock. 

 Then the cargo 

 was either 

 hauled up by 

 the ship's der- 

 ricks piece by 

 piece, or it was 

 run up the gang- 

 way by the 

 truck load. But 

 with the eleva- 

 tor designed by 

 Harry Barlow, 

 ofSeattle, Wash- 

 ington, an entire 

 platform of ma- 

 terial can be 

 quickly carried 

 up to the ves- 

 sel's deck at 

 once. And if 

 the tide is out, 

 the light sound 

 boat carrying 

 the elevator 

 steams from the 

 dock to the vessel anchored near by. 



A small electric motor mounted on the 

 top of the elevator structure furnishes the 

 power for the half dozen cables used. The 

 motor controls are placed at any point that 

 affords the operator an unobstructed view. 

 After the operator has brought the plat- 

 form to the level of the loading dock, the 

 filled platform can be easily raised up 

 to the deck of the largest steamer. Level 

 trucking is thus afforded in place of truck- 

 ing up or down steeply inclined gangways. 

 This fact makes the elevator indispensable 

 for loading explosives or fragile wares. 



