346 TEAXSACTIOXS AND PROCEEDINGS OF [Sess. lvi. 



present site ; and my example, Qucrcus'rubra, No. 61, proves 

 that even after the total loss of the young wood of a season, 

 a tree may rapidly recover perfect health. 



On a IJapid Method of Shaepening Knives for Section - 

 CUTTING. By A. X. M' Alpine, B.Sc. 



A plane iron of the best quality is most suitable for my 

 form of microtome. A rectangular strip of steel is fastened 

 across the plane iron in such a way that the anterior edge 

 of the rectangle is parallel to the edge to be sharpened. By 

 this attachment, the plane iron is rendered virtually hollow 

 ground and the sharpening is accordingly both rapid and 

 true. When sharpening, the edge of the iron and the 

 anterior margin of the steel band are ground together on the 

 stone, and the edge is finished on a leather strop which ought 

 to be fixed to a rigid support in order to prevent rounding. 



Mr FoRGAN asked leave of the Society to say that the 

 device which Mr M'Alpine had brought before the Society 

 was not a new one. It was referred to in Holtzappel's 

 " Mechanical Manipulation " published at least forty years ago 

 and might be then of very old date. Mr Forgan said he had 

 used it himself more than thirty years ago when sharpening 

 plane irons, to which it gave a very fine and equal edge. 

 The statement in regard to it will be found in the second 

 volume of Holtza2)pel, page 497, and is to the following effect : 

 "When tlie minute chamfer of the plane iron is almost 

 parallel with the sole of the plane, it will for a short time 

 be entirely effective. Thus as an experiment, drive the iron 

 a very small quantity through the tole, and sharpen it by 

 allowing the oilstone to rub both on the edge and on the 

 wood beliind, tliis will produce a very accurate edge, and the 

 iron when set back, will cut beautifully." The second 

 volume of Holt;^appel was published in 184G by Holtzappcl 

 & Co., G4 Charing (Jioss and ]27 Long Acre. 



With reference to Mr M'Alpine's statement that he used 

 a leather strop to fine the edge of the plane iron after it 

 came from the hone, Mr Forgun pointed out that the same 

 subject was discussed at tlie IJoyal Scottish Society of Arts 

 about five years ago, when tlie late ]Jr Sang stated during 

 the discussion that he never used a strop to improve the 



