468 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



strength of wood, its resistance to splitting, and the theory 

 of the use of the wedge, the axe, etc. The importance of these 

 matters he shows to be very great, because great industries 

 depend upon the facility with which wood can be split, and 

 upon the applicability of certain kinds of wood. Having 

 deduced a few simple formulae to express the strengths of 

 woods and the power of the wedge, he develops a formula 

 for the force with which an axe is handled, and shows what 

 curve should be given to the face or cheek of the axe in order 

 to secure, under certain conditions, the least waste of power. 

 By means of these formulae he is able to demonstrate that 

 the splitting efficiencies of the best axes made in Vienna, 

 Prague, and America are to each other as 13.3, 9.2, and 4.9 

 respectively ; and, applying his formulae to the elaborate ex- 

 periments of Nordlingen, he is able to deduce the absolute 

 ease with which various woods can be split. Annals Maria- 

 brilnn Forest, I., 184. 



THE CONSTRUCTION OF WINDING STAIRCASES. 



In Major Elliott's Report on European Light-houses he 

 notes that in several cases the stairs are circular, and ap- 

 parently self-supporting, one end only being built into the 

 Avail, as in the Treasury at "Washington. This method of 

 stair-building is, he observes, universal in Europe, both in 

 private and public buildings. The most recent light-house 

 towers of the American system are constructed with conical 

 interior walls, and iron staircases winding around the in- 

 terior of the cone. European towers are generally construct- 

 ed with an exterior conical and an interior cylindrical wall, 

 leaving an unnecessarily large unused space between the two. 

 The amount of masonry in the American system is the same 

 as in the European, and is better calculated to resist the 

 overturning effect of the severest gales. Elliott's European 

 Light-house System^. 106. 



walker's patent rolling cars. 



Amonir other interesting emnneerino; and mechanical nov- 

 elties, we find reference in The London Iron to what is called 

 Walker's Patent Rolling Cars, in which the wheels of an or- 

 dinary railroad track are replaced by cylinders, with wheel- 

 heads, and which when combined in pairs, as ordinary car- 



