34 



SCIENCE, 



[YoL. VI., No. 127. 



proposed is very briefly this : to lift the vessel 

 by an ordinary lifting-dock, distributing and 

 equalizing completely the weight of the vessel 

 by a system of hydraulic presses before the 

 weight is brought upon the carriage which 

 is to transport it. This is all done under the 

 water, as the vessel rises out of it, and in 

 such a manner as to be perfectly safe and easy 

 for the vessel. The weight is finally placed 

 upon the carriage in such a way that there is 

 no more weight upon one wheel, or upon one 

 part of the carriage in its length or width, than 

 upon another. The weight upon no wheel will 

 be over eight or nine tons, although they will 

 be tested to twenty tons when manufactured. 

 The whole load is transferred to the wheels b}^ 

 means of powerful springs, which will also be 

 tested to twenty tons, and none of which will 

 have imposed upon them in practice a weight 

 of over eight and a half or nine tons. These 

 springs not only give a perfect cushion for the 

 vessel and carriage while being transported, 

 but also serve to take up any slight irregulari- 

 ties there may be in the track. The system 

 of supports designed, and shown in the work- 

 ing model, gives an area of support under 

 the vessel from fifty to seventy-five times as 

 great as that in the best lifting-dock in the 

 world ; and, moreover, these supports com- 

 pletely adjust themselves to the model of the 

 vessel in each case. As it has been said fre- 

 quently by practical experts in designing and 

 building docks, and handling vessels in them, 

 the desideratum is to have a sufficient number 

 of adjustable supports, and this has been 

 sought for in the plans for the work as shown 

 in the model. 



The railway road-bed will be about 50 feet 

 in width ; the width between the outer rails, 

 about 30 feet. There will be six of these rails, 

 weighing from 100 to 125 pounds per lineal 

 yard. All six rails will be connected by a 

 long steel-plated tie, set into two feet of 

 broken stone ballast or concrete, as the case 

 may be. The locomotive power as designed 

 is to consist of engines of from 75 to 100 tons, 

 each of which will haul at least 3,000 tons on 

 a grade of as much as 40 feet to the mile ; so 

 that two, or at the most three, such locomotives 

 will haul the maximum load. The grades are 

 very light. Much of the line of railway is 

 practically level. The maximum gradient, of 

 which there is onl}^ one length of about 12 

 miles, is one per cent, or 52.8 feet per mile. 

 The change between grades will be made by 

 the ordinary vertical curve, but a very flat one, 

 — one that will change from a straight line 

 two inches in 400 feet. The railway is prac- 



tically straight, the minimum radius being 20 

 miles. The line as laid down on the isthmus 

 has curves of from 20 to 53 miles radius. At 

 five points on the line, in order to avoid heavy 

 mountain cuttings or very high embankments, 

 a change of direction will be made by floating 

 turntables, — a simple and economical device 

 in first cost and operation, on which the vessels 

 will be turned about while resting on a cushion 

 of water. The whole line has been very 

 carefully surveyed, and is practicall}^ located. 

 Careful examinations have been made to as- 

 certain the character of the foundations, both 

 for the road-bed and for the masonry structures. 

 The result of these examinations shows that 

 there is no bad or even questionable ground 

 anywhere between the two termini. The ac- 

 companying map shows the topography of the 

 country and the route of the railway, the river 

 to be navigated and the harbors on the two 

 sides. 



It will be seen from the foregoing that the 

 vessel, when lifted out of the water, is really 

 water-borne on a system of columns of water 

 under pressure, and that, in the position given 

 by this hydraulic system, she is transported 

 across the isthmus. It will also be seen and 

 appreciated by every person who is accustomed 

 to travel on the ocean, that the strain to the 

 vessel by the methods proposed can never be 

 so great as that which she must undergo every 

 time she ofoes to sea. E. L. Corthell. 



THE WATER-SUPPLY OF BRESLAU. 



The results of Hulwa's numerous examinations of 

 the waters of Breslau made during the years 1876-81, 

 and which, up to that time, had appeared only in 

 fragmentary official reports hardly obtainable even 

 by specialists, were brought together into a single 

 paper on the occasion of the German health exhibi- 

 tion in 1882-83. This paper, recently published, is 

 of great value to all interested in water-supply. 



As far as the well-waters are concerned, the nu- 

 merical results are given only in selections and aver- 

 ages, and are, indeed, mainly of local interest. The 

 story is essentially the same as may be told of any 

 compactly built city, especially of the older parts, 

 where the same houses have been occupied for hun- 

 dreds of years. Of a hundred and fifty wells exam- 

 ined, less than ten per cent furnished water really 

 good enough to use, and only two or three water 

 which was above all suspicion. 



Since the year 1871, Breslau has enjoyed a supply 

 of water from the river Oder. The works are situ- 

 ated above the city, and the water is subjected to a 

 thorough filtration through beds of sand and gravel. 



Beitrdge zur schioemmkanalisation und wassermrsorgung 

 der stadt Breslau. Von Dr. Franz Hulwa. (Erganzungshefte 

 zum Centralblatt fiir allg. gesundheitepflege, I. ii. Bonn, 1884.) 



