MECHANICS AND USEFUL ARTS. 83 



of windward great-circle sailing. The other modification of this 

 sailing had been brought into successful use ; but windward sail- 

 ing, although it appeared most simple, had been generally mis- 

 understood by practical men. Some had obtained charts having 

 great-circle routes laid down. If they were driven from this track 

 by adverse winds, they returned as soon as the wind would, per- 

 mit them, not perceiving that when they had quitted one great 

 circle there was another great circle, which was their nearest 

 route. Others imagined that this sailing consisted in going a cer- 

 tain number of miles to the northward. The rule was simple. 

 "Find the great-circle course, and put the ship on that tack 

 which is the nearer to the great-circle course. In January last 

 he was invited by Mr. Ashbury to prepare sailing directions for 

 the Cambria yacht, which he did. These directions were shown 

 by a chart. It consisted of the great-circle course, corrected for 

 variation, for every part of the Atlantic it was probable that a 

 vessel should pass. All the mariner had to do was to ascertain 

 his approximate position, and then he would find by inspection 

 how to keep the ship's head by compass. The distance from the 

 place of destination was also given by another chart containing 

 the position of both yachts at noon, for each day. Mr. Towson 

 showed that the " Cambria" saved the race by superior naviga- 

 tion. This sailing gave the greatest advantage when the distance 

 of longitude was greatest; and thus the " Cambria" attained all 

 the advantage that this sailing could afford in the first 5 days, 

 which was about 110 miles ; afterwards the superior power for an 

 ocean race possessed by the " Dauntless " prevailed, and reduced 

 this advantage to a minimum. 



THE CABLE SYSTEM OF RIVER NAVIGATION IN GERMANY. 



The Frankfort correspondent of the Chicago "Republican," 

 writes that the cable system of navigation is, at the present time, 

 making rapid progress in Germany. This system prevails on 

 the whole course of the Elbe through the kingdom of Saxony, and 

 to some extent in the neighborhood of Magdeburg, and its exten- 

 sion into the interior of Bohemia on the one hand, and to Ham- 

 burg on the other, is projected, and is expected to be completed 

 in a short time. On the Danube and its affluents the laying of a 

 wire cable by the Danubiau Steamship Navigation Company 

 (Donau-Dampf-schiff farthgeselschaft) is being quickly and ener- 

 getically prosecuted. The laying of one along the Rhine in West- 

 phalia has already been completed. It is also intended to make 

 this fresh invention available for the smaller streams of Ger- 

 many, as, for instance, on the Saale and the Unstrut, for which 

 the civil engineer, Opel, of Merseburg, a little while ago, recom- 

 mended the laying of a wire cable instead of the proposed con- 

 struction of a towing-path. This system of cable navigation 

 (either by ropes or chains) is likewise cheaper than the use of 

 towing-paths, and by this method, also, the possessors of land and 

 other property on the banks of rivers are spared many inconven- 



