''!Craai;Fi'bTi«7a 'J -Ro?/aZ Microsco;piccd Society. 75 



IV. — On a New Instrument for Cutting Thin Sections of Wood. 

 By M. MoucHET, Hon. F.E.M.S. 



(^Read before the Royal Microscopical Society, January 12, 1870.) 

 (Communicated by the President.) 



I HAVE remarked often that thin sections of wood, when submitted 

 to microscopic investigation, exliibited on one of their sides beards, 

 owing to the wood offering a very shght resistance to the knife 

 after ha\ing been cut through |rds or |ths of its diameter. I 

 have been therefore induced to look for a remedy against this 

 inconvenience, and I think I have found it. I am confident that 

 the question consists in being able to cut the wood out the whole 

 of its circumference. 



The only difference between the former machine and the one which 

 I ha\'e now made hes in this, that the knife cuts the wood circularly. 



This knife has a very strong and semicircular blade, and is 

 fixed by means of screws to a handle that is long enough to form 

 a lever, the fastenmg-poiut lying in the upper part of the knife 

 5 centimetres distant li'om the centre of a copper-plate 19 centi- 

 metres in diameter. The surface of this plate is perfectly even, 

 and the knife is, as it were, adherent to it. 



This knife is sloped underneath in order to avoid rubbing, and 

 kept in its place by a large-headed screw. 



In the centre of the plate may be fixed, when and as one 

 pleases, small tubes of different cliameters, which tubes are to 

 receive the stalks of wood that are to be cut. Underneath the 

 plate there is a finely-notched wheel which, through a pinion and 

 handle, causes the tube to be moved, and the wood contained in 

 it, and destined to be cut in thin sections, to tm-n round. 



The whole system previous to the operation is maintained in 

 a press-vice, or fixed on the border of a table by a clamping-screw. 

 In this way both hands are free, and while the right hand is 

 acting on the knife-lever, the left manoeuvres the pinion stalk- 

 handle, and the wood is attacked circularly and easily cut to its 

 centre. Complication is the only defect of the system; but it 

 cannot be avoided where catchings are used. I hardly need say 

 that in this httle machine, as weU as in all those of the same kind 

 that are carefully made, the wood is brought forward by a micro- 

 metric screw, the head of which is divided in order to get the thin 

 sections to have the thickness required. 



In this too summary note I intend nothing else but to indicate 

 the way in which wood is to be cut when ^vishing to avoid the 

 beards which I have spoken of, and which many a one must have 

 remarked in certain microscopic preparations. 



Note. — At the President's request, BI. Mouchet communicated this brief 

 notice of his Cutting Machine, for which he received the "Gold Medal of 

 Honoiu-" at the late Paris Exposition. — Ed. M. M. J. 



