444 



THE MICROSCOPE. 



fig. 214. Cwttireg Machine. 



ha., should be soaked in essential oil, alcohol, or ether, before they are 

 mounted as transparent objects. A razor may be fixed to the bench for 

 the purpose of cutting these fine sections, or a fine plane will answer 

 very well. The best instrument is the one used by Mr. Topping, 



fig. 214. a 6 is a flat piece of ma^ 

 hogany, seven inches long and four 

 wide, to the under surface of which 

 is attached, at right angles, a piece 

 g of same size as a 6. d representai 

 a fla,t plate of brass, four inches long 

 and three wide, screwed to the upper 

 surface oiah ; 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 ^ work., 

 ing in a nut, and having a disk k 

 exactly adapted to the bore of the 

 tube ; this disk is connected with the upper-end of the screw, and is 

 moved up or down by it. c is another screw connected with a curved 

 piece of brass h, which is capable of being carried to the opposite side 

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

 tube e, and is raised or depressed by the screw/; whilst, before cutting, 

 the curved piece of metal h should be firmly pressed against it by the 

 screw 6. 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.-^li the wood be green, it should be 

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

 alcohol, to get rid of all resinous matters. 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 placed in water 

 again, as in the case of the green wood. If the machine to be employed 

 be such as described, the wood (if sufiiciently 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 firmly : these will have the advantage of affording support, and if 

 necessary, may be cut with the specimen, from which they may after^ 



