138 PHILOSOPHICAL TRANSACTIONS. £aNNO 1674. 



work on it : b the hammer, in fig. 6, for beating and bruising the stuff; which 

 may be of 6 pounds weight, and have the head about 3 inches square, to work 

 with both hands ; but to work with one hand, or for a youth to use, let it be 

 of about 3 pounds weight, and the head about 2 inches square. The surface of 

 one end of these hammers is best to be smooth ; but that of the other dented, 

 the better to enter into the stuff for the greater dispatch. They are to be well 

 steeled at both ends. The handles of these hammers may be about a foot long; 

 the larger ought to be somewhat longer, cd is the knife in fig. 4, to cut the 

 bruised stuff; which must be 8 or Q inches broad, and near as much in depth, 

 made like a tobacco-knife, with a handle to work. This knife must be fastened 

 to the block at the two opposite sides, that are to be hollowed by two grooves, 

 efgh in fig. 5, and iklm in fig. 4 ; and this fastening is to be performed by 

 two pieces of iron, to be fitted in the said grooves, to hold and guide the knife 

 in working ; the one piece nopq, in fig. 4, is to be fastened to the end of the 

 knife c by a pin r, passing through three holes ; and this end is to be screwed 

 into the groove efgk in fig. 5, by a couple of screw-pins ; the other piece 

 stuxyz in fig. 4, being forked, is to receive the other end of the knife d ; and 

 the solid square part thereof, iklm, is to be fastened in the groove under it, by 

 two iron plates uoc, a, under which it must run in the said groove, so as that it 

 may be slipped out from under it, and laid by, when the machine is not used ; 

 when also the piece at the other end may be unscrewed and laid up. 



The two long squares on one end of the block, in fig. 4, viz. 5, 6, 7, 8, are 

 two iron-plates to be fastened where the knife, moving in a tit cavity, is to 

 cut the bruised stuff between them. And of these plates, that which lies next 

 the end, is to be laid a little lower, the block being there pared accordingly, so 

 that the stuff may fall off from the end of the machine the quicker, as your left 

 hand furnishes the knife with the bruised materials, whilst the right hand is 

 cutting them. Let the hollow place, where the knife cuts, be as near as may 

 be, so large only, that the knife may easily fall and rise ; and let the block be 

 hollowed under the cutting hole, and sloped off at that end, for the stuff to fall 

 off as it is cut by the knife. 



A further Consideration on Snails. By Mr. Martin Lister. N*' 105, p. q6. 



I herewith send you the first part of our tables of snails, and some queries 

 upon that subject ; also the lively figure of each shell for illustration, done by 

 Mr. Lodge. I reserve by me the sea-shells and rock-stones. Again, in that 

 part of the tables, you have from me, authors are very little concerned ; in the 

 other, of sea-shells and stone-like shells, there are many authors, which are to 

 be consulted and taken in, if possibly we can understand them, treating of the 



