July 10, 1885.] 



SCIENCE, 



33 



no evidence for or against the danger of using 

 bad water. The influences are felt principally 

 b}' the weaker members of a community. 



As regards the specific objections which may 

 be raised to using the water of city wells, it 

 may be said, in the first place, that the evidence 

 is prett}' clear that water contaminated with 

 sewage does at times give rise to low fevers. 

 Though it is diflftcult to furnish satisfactory 

 proof of the statement that the use of contami- 

 nated water tends to lower the general condi- 

 tion of health of those who habitually use it, 

 those who have paid most attention to the sub- 

 ject unanimously agree that pure water is as 

 important as pure air for the preservation of 

 good health. One of the chief dangers in the 

 use of water contaminated with sewage is, that, 

 by establishing connection between the sick 

 and the well, it contributes to the spread of 

 some forms of epidemic disease. As is well 

 known, it is now held by many of the highest 

 authorities that in some diseases the organ- 

 isms which are believed to be the active causes 

 are given off from the patients with the alvine 

 discharges. If, now, by any means, these or- 

 ganisms or their germs are introduced into the 

 system of a well person, the diseased condition 

 is set up. What more efficient method of dis- 

 tributing these organisms than drinking water 

 which is contaminated with the contents of 

 cesspools ! Exactl}" what forms of disease 

 may be spread in this way, it is diflftcult to say ; 

 but there is strong evidence in favor of the 

 view that typhoid-fever and cholera are among 

 them. Over and over again, outbreaks of ty- 

 phoid-fever have been traced with practically 

 absolute certainty to the use of water known 

 to be contaminated b}^ sewage. In regard to 

 cholera, the evidence is quite sufladent to jus- 

 tif}^ the destruction of all city wells. 



Ira Remsen. 



THE SHIP-RAILWAY BETWEEN THE 

 ATLANTIC AND PACIFIC. 



The article by Mr. Hubbard, in Science of 

 Nov. 4, 1884, on canal routes between the 

 Atlantic and Pacific, discussed briefly the ad- 

 vantages of the three routes and methods pro- 

 posed. The object of the present paper is to 

 present the scientific and commercial reasons 

 why the ship-railway across the Isthmus of 

 Tehuantepec maj' be superior to either the 

 Panama sea-level canal, or the Nicaragua lock 

 canal. 



It is estimated that $50,000,000 will be 

 ample to put the ship-railway into operation 

 for the transportation of vessels of 5,000 tons. 



The estimated cost of the Nicaragua canal on 

 a cash basis is $140,000,000, and of that at 

 Panama, as high as $350,000,000. 



The route via Panama, between Liverpool 

 and San Francisco, is about 700 miles longer 

 than b}^ Tehuantepec ; between New York and 

 San Francisco, about 1 ,200 miles ; and between 

 New Orleans and San Francisco, about 2,000 

 miles. Probably 1,000 miles excess of dis- 

 tance would be a fair average. 



The time in transit across the isthmus would 

 be at least three days shorter at Tehuantepec 

 than at Nicaragua for either a steamer or sail- 

 ing-vessel. The Suez canal, which is 100 miles 

 in length, delays a steamer 48 hours in transit, 

 or her passage is at the rate of about two miles 

 per hour : two-thirds of the distance is through 

 the lakes, and there are no locks. At Nica- 

 ragua, about one-sixth of the distance only is 

 through an open lake ; and there will be from 

 twelve to twenty locks, at each of which a 

 vessel will be detained nearly an hour. The 

 time required for passage, therefore, will be 

 about four days ; so that, although the total dis- 

 tance is shorter than at Panama, the time re- 

 quired for a steamer would be about the same. 



In the article by Mr. Hubbard above referred 

 to, reference has already been made to the 

 favorable situation of Tehuantepec with ref- 

 erence to the trade-winds. 



It is also hoped that the maintenance will 

 cost much less per annum than that of either 

 canal. The Panama canal being below the 

 level of the sea, with the slopes of its enor- 

 mous cuts exposed to the wash of the tropical 

 rains, the diflSculty of removing the material 

 washed into its prism, and the controlling of 

 the Chagres River, make the maintaining of 

 the ship-channel difficult and expensive. At 

 Nicaragua the conditions are nearly similar. 



The ship-railway will not be subject at an}' 

 point to the ravages of fioods. It will be built 

 over its entire length, on the solid ground, 

 with excellent materials at hand for construc- 

 tion and maintenance. On either side is a 

 natural harbor, which with small expense, by 

 the construction of jetties, will give two excel- 

 lent ports. The climate is remarkabl}' healthy, 

 and native labor abundant and cheap. It is 

 located in a country which has a comparatively 

 strong government. 



The estimated total cost of maintenance and 

 operation in lifting, hauling, and placing the 

 vessel with its cargo in the water again, is less 

 than thirty cents per ton of cargo carried. 



The great doubt which must exist iu the mind 

 of the reader is in the practicability of lifting 

 and haulino; a loaded vessel. The method 



