L. MECHANICS AND ENGINEERING. 445 



sleeper, which latter is often found, especially in narrow- 

 gauge roads, to take up too much room, and to occasion fre- 

 quent repairs. In India iron sleepers have long been in 

 successful use the destructive habits of the ants rendering 

 the use of timber quite impossible. 



SINGLE-RAIL STEAM: TOWAGE ON CANALS. 



The following is a description of a method of steam tow- 

 age lately introduced on the Bourgogne canal in Belgium. 

 The tow-path is laid with a single rail, weighing some six- 

 teen pounds to the yard, and fixed on traverses placed 3.2 

 feet apart. The locomotive has four wheels, two of which 

 are placed directly along the axis of the vehicle, one in ad- 

 vance of the other, and the other two opposite each other at 

 the sides. The first-named pair are directing, and the last- 

 named driving wheels. The directing -w-heels are grooved 

 and fit the rail ; the others have rubber tires that give pur- 

 chase on the macadamized road. By means of simple mech- 

 anism the weight of the engine may be thrown either on the 

 driving or directing wheels at pleasure. In the first case 

 the maximum, and in the latter the minimum of adherence 

 is obtained, to correspond to the condition of a loaded or 

 empty boat. A single road is employed with relay engines 

 provided at suitable distances. Each locomotive tows one 

 boat, and when a meeting takes place of two traveling in op- 

 posite directions, the engines change boats and retrace their 

 paths. The single rail system has already been satisfactorily 

 tested for short distances on the Belgian canals; and the 

 system here described will extend its application over a dis- 

 tance of 150 miles. The locomotives are described as weio'h- 

 ing four tons each, and travel, according to statement, 3.1 

 miles per hour, with full boats carrying a cargo of 150 tons 

 each. 1 1 D, XIX., 54. 



CAST-STEEL WIRE ROPES. 



According to a Prussian mining journal, cast-steel wire 

 ropes have been substituted in many mines in Westphalia for 

 those of iron, with excellent results. Experience in all cases, 

 however, indicates that steel wires must be greased at least 

 once a week, and that it is advisable to lay the rope aside 

 upon the slightest indication of brittleness in any of the 



