14 



PAL^ONTOLOGICAL BOTANY. 



for safety it may be annealed to a straw colour. The pestle 

 is merely a cylinder of steel, fitting the hollow mortar but 

 loosely, and having a ledge or edging of an eighth of an inch 

 projecting round it, but sufficiently raised above the upper 

 surface of the mortar, so as not to come in contact while 

 pounding the diamond. The point of the pestle ought only 

 to be hardened and annealed to a straw colour, and should 

 be of course convex, fitting the opposing and equal concavity 

 of the mortar. The purpose of the projecting ledge is to 

 prevent the smaller particles of diamond spurting out when 

 the pestle is struck by the hammer." 



Mr. Bryson has contrived an instrument for slitting fossils. 

 The instrument is placed on the table of a common lathe, 



Fig. 8. 



which is, of course, the source of motion (Fig. 8). It con- 

 Fig. 8. Mr. Bryson's instrument for slitting fossils. A very simple 

 slicing and polishing machine has been invented by Mr. J. B. Jordan of 

 the Mining Record Office, and is sold by Messrs. Cotton and Johnson, 

 Grafton Street, Soho, London. It costs about £10. 



