April 1891.] BOTANICAL SOCIETY OF EDINBURGH. 91 



the wood to a greater depth than 2^ inches. Along with 

 the instrument, at the prices quoted, are supplied a hook of 

 directions, a magnifying glass of low power, and a hottle of 

 red aniline crystals, hesides two necessary accessories, which 

 will be described presently. 



A 



Shortly described, the instrument consists of a hollow 

 handle B, C, into which, after removal of the screw-cap B, 

 the boring-tube and accessories fit when not in use. The 

 other end (C) of the handle is also provided with a screw- 

 cap, which closes a small chamber designed to contain some 

 lubricant, such as lard, the application of which to the boring- 

 tube facilitates its entrance into hard wood, and also prevents 

 its rusting. 



The actual borer consists of a tube of hardened steel 

 (A, D),* whose internal diameter is slightly greater at D than 

 at A. This facilitates the withdrawal of the little cylinder 

 of wood that it is desired to extract from the tree. The end 

 of the borer at A has a cutting edge, and for about an inch 

 back from this extremity it is furnished externally with three 

 threads of a cutting screw. 



When it is desired to use the instrument, the boring-tube 

 is withdrawn from its receptacle, and is fitted into a slot in 

 the middle of the handle. It is then pressed against the tree, 

 being steadied, if necessary, by the left hand till it has fairly 

 caught the wood, into which it is forced by the rotating 

 motion imparted to the screw by turning the handle. 



Having inserted the borer to the desired depth a steel 

 pin, of the same length as the borer, with a large flattened 

 brass head is brought into requisition. This pin is convex 



* At D the piu and brass trough are seen projecting from the tube. 



