414 



SCIENCE. 



[Vol. XIV. No. 359 



steam- passages are shown at G, and the exhaust-passages at H. 

 The reversing-valve acts inside the main valve, the reversal of the 

 engine being effected by giving the inner valve a half-revolution in 



the outer valve, thereby changing the register of the steam-pas- 

 sages. The reversing-lever is shown in the plan of the valve-seat, 

 Fig. 6. A cross-section of one of the main bearings with anti- 

 friction metallic bushing is shown at Fig. 7. These bearings are 



fTTI. . 



■. rm cQi rm 



im . 



.4. i (—, ) X. 



FIG. 4. 



FIG. s- 



conical, and milled through, so that all wear may be easily and 

 quickly taken up by turning the adjusting nut on the bearing casing. 

 The connecting-rods are of the skeleton pattern, with self-oiling 

 bronze bo.xes lined with anti-friction metal. 



These engines are made by special tools in such a way as to in- 

 sure that all like parts are interchangeable, thus facilitating repairs. 

 The plain non-reversible engine made by the same manufacturers 

 is the same as the engine shown, except that it has no reversing- 



valve, and is provided with a pulley on the shaft instead of a cou- 

 pling. In the larger sizes of these engines they will be made com- 

 pound, and also automatic, special attention being paid to their 

 adaptability for electric lighting and similar purposes. Among 

 the advantages claimed for this engine are that it is economical. 



FIG. 7. 



light, durable, simple in construction, and easy to operate, having 

 no links, eccentrics, valve-stems, stuffing-boxes, nor dead-centres. 

 It is said to afford greater power in smaller space than any other 

 engine ever constructed, and to have the most positive valve-gear 

 ever designed. 



ELECTRICAL NEWS. 



New Insulating Compound. — A new insulating compound 

 which finds favor among manufacturers of electrical instruments 

 and machinery in France consists of one part of Greek pitch and 

 two parts of burnt plaster by weight, the latter being pure gypsum 

 raised to a high temperature and plunged in water. The mixture, 

 when hot, is a paste, and can be applied by a brush or cast in 

 moulds. It is amber-colored, and can be turned and polished. Its 

 advantage is said to be endurance of great heat and moisture with- 

 out injury to its insulating properties. 



Electric Traction. — A large and appreciative audience lis- 

 tened to the reading of a paper by S. Dana Greene, on the " De- 

 velopment of Electric Street-Car Traction," at a meeting of the 

 New York Electrical Society on Dec. 11. In Mr. Greene's opinion, 

 the storage-battery system of electric traction is the ideal one for 

 roads of easy grades, though it is yet far from perfect. He pre- 

 dicts, however, that a few years more will develop a wonderful in- 

 crease in its efficiency and reliability. 



