522 



Popular Science Monihly 



ease as if the vessel were tied to a wharf. 

 Many thousands of barrels of oil are 

 thus shipped from Tuxpan each year. 

 The success of the first lines at Tuxpan 

 stimulated the installation of many 

 others at, or near the port, until the 

 submarine method of loading oil has 

 become standard in the region. The 

 method by which the pipe lines are laid 

 is no less interesting than their function. 



How the Pipe 



Line Is Laid 

 A trench is 

 first dug 

 through the 

 sand dunes 

 near the beach, 

 until a smooth, 

 even grade is 

 secured down 

 to tidewater. 

 On this grade 

 short ties are 

 laid back from 

 the beach. On 

 these ties light 

 rails are laid, 

 the gage being 

 less than afoot. 

 On this narrow 

 railway small 

 carsor"dollies" 

 ride. The pipe 

 sections arc 

 connected on 

 shore beside 

 this narrow- 

 gage track, 

 lifted upon the 

 "dollies," and 

 thus trans])or- 

 ted into the 

 ocean. A steamshij) on 

 the bar plays the part 

 motive to the dollies, 

 emi)loyed. 



As a rule the lines are made ti|) of 

 8-inch steel [)i[)eand api>roximale a mile 

 and a half in length. l'"re(|nently a small 

 hoisting-engine has to be installed alcmg 



the track to aid the steamship at sea in 

 pulling the line. By fastening a cable 

 back of a coupling on the line and run- 

 ning it over one of the drums on the 

 hoisting engine, substantial aid can be 

 gi\'cn in this work of hauling. 



I 



The fog-stick is run out from the steamer on a 

 steel towHne by means of a pulley 



the other side of 

 of hauling loco- 

 a hauser being 



A Fog- Stick Guide for Traffic on 



the Great Lakes 

 N very foggy weather the barges 

 towed by steamers on the Great 

 Lakes are often lost to sight, so that the 

 safety of both steamer and barge is 

 jeopardized. The fog-stick shown in the 

 accompan\'ing illustration was designed 

 to meet this condition. It is sent f)Ut 

 from the steamer on the steel towline 



by means of a 

 pulley or block, 

 and is run up 

 close enough to 

 the barge to 

 be always visi- 

 ble to the man 

 at the forward 

 wheel and to 

 indicate the 

 direction in 

 which the tow- 

 line is leading 

 and conse- 

 quently the 

 relative po- 

 sition of the 

 steamer. 



Rope guys 

 hold the fog- 

 stick at the 

 retjuired dis- 

 tance from the 

 bow of the boat 

 and a weight 

 composed of a 

 bag of sand 

 keeps it up- 

 right. At night, 

 or w h e n e v e r 

 the fog is (hick 

 enough to war- 

 r a n t it, a 

 lantern is suspended from the pole. 



Why the Color of Sea Water Is Blue 

 or Green 

 ^IIV is the ocean blue? Because of 

 the rellection of the sky? This 

 accoimts for some of the color but it is 

 largely a matter of saltness and density. 

 In the tropics where the inten.se hea^ 

 and rapid e\aporation cause the water 

 to be much saltier the blue is vivid, while 

 the further one goes toward the poles 

 the greener the hue becomes until it is 

 almost as \i\id as the tropical azures. 



w 



