338 MANIPULATION. 



and four wide, to the under surface of which is attached, at 

 right angles, a piece, G, of the same size as A B. D represents 

 a flat plate of brass, four inches long, and three wide, screwed 

 to the upper surface of A B ; to the middle of this plate is 

 attached a tube of the same metal, E I, three inches long and 

 half-an-inch in diameter, and provided at its lower end with a 

 screw, F, working in a nut, and having a disc, K, exactly 

 adapted to the bore of the tube ; this disc is connected with 

 the upper end of the screw, by which it is moved up or down. 

 C is another screw connected with a curved piece of brass, H, 

 which is thus capable of being carried to the opposite side of 

 the tube. The piece of wood about to be cut is put into the 

 tube, E, and is raised or depressed by the screw F, whilst, 

 before cutting, the curved piece of metal, H, should be firmly 

 pressed against it by the screw, C. This instrument is to be 

 fastened to the edge of a bench or table, where it may be 

 always kept ready for use. The knife * to be employed may 

 be one constructed for the purpose, or a razor ground flat on 

 one side will be found to answer very well. 



Method of making Sections. — If the wood be green, it should 

 be cut to the required length, and immersed for a few days 

 in strong alcohol to get rid of all resinous matter; when 

 this is accomplished, it may be soaked in water for a week or 

 ten days, it will then be ready for cutting. If the wood be dry 

 it should be first soaked in water and afterwards immersed in 

 spirit, and before cutting be placed in water again, as in 

 the case of the green wood. If the machine to be employed 

 be such as described in page 336, the wood (if sufficiently 

 large) should be cut so as to fit tightly into the square hole, 

 and be driven into it by a wooden mallet; if, on the contrary, 

 it be round, and at the same time too small for the hole, 

 wedges of deal or other soft wood may be employed to fix it 

 firnaly; these will have the advantage of affording support, 

 and, if necessary, may be cut with the specimen, from which 

 they may afterwards be easily separated. The process of 

 cutting consists in raising the wood by the micrometer screw, 



* The machine, together with a knife, can be obtained of Mr. Topping 

 at the low price of sixteen shillings. 



