240 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the former. This glass wedge travelled along a bed, or base-plate, also 

 of glass, being kept in position by means of a slot cut along its surface. 

 As the wedge was propelled forward by the screw it raised a vertical 

 plate, accurately adjusted at right angles to the base-plate, and as free 

 as possible from movement other than that imparted to it by the wedge. 

 To this vertical plate, the slide, or disk to be ruled upon, was attached 

 by means of a suitable cement. A platform, for the support of a sliding 

 diamond carriage, bridged the base-plate and wedge at a suitable height, 

 being, of course, arranged transversely to and in front of the vertical 

 slide. 



With this roughly constructed apparatus I was able to produce ruled 

 bands, or groups of lines, ranging from 5000 up to 50,000 lines per inch. 

 The apparatus has since been completely rebuilt, being variously 

 modified and altered in accordance with experience gained, and the 

 greater precision demanded by the class of work subsequently under- 

 taken. 



My work has tended mainly in the direction of perfecting rulings 

 for micrometric measurements, and for test purposes. To accomplish 

 this, I have had so to modify and improve the apparatus with which I 

 first commenced work, as to render it capable of precise and accurate 

 movements much less than 0*00001 in. ; also to select and mount 

 diamonds with knife edges of a fineness or keenness equal to the group- 

 ing together of lines less than ' 00001 in. apart, and yet of such strength 

 and durability as to be capable of producing many thousands of such 

 lines without material alteration in character ; and, last, but by no 

 means least, so to mount these rulings as to exhibit them in the best 

 possible manner, while at the same time insuring their permanence as 

 microscopical preparations. 



The selection, setting and cutting action of the diamond are of the 

 utmost importance. Nearly all the stones I have used have been 

 obtained from Bingara, N.S.W. 



I have tried Brazilian and West Indian diamonds, also the black 

 diamond or carbonado, none of which appear to possess any advantage 

 over those obtained from New South Wales. Some little time ago I 

 received from Dr. van Heurck, of Antwerp, two stones which had been 

 specially prepared after the method of Nobert, by one of the most 

 skilful diamond workers in that city, neither of which was of any value, 

 the cutting edges being much too blunt for fine work. My own method 

 of preparation is to carefully break the stones so as to insure fracture 

 parallel with some of the numerous cleavage planes. The fragments so 

 obtained are examined under the Microscope as to the perfection or 

 otherwise of the angles or edges and faces forming them, the promising 

 pieces being put aside for trial. Good results have also been obtained 

 with stones upon which large facets had been ground on the outer or 

 natural face and afterwards broken so that one face of the knife edge 

 was artificially formed, while the other followed the line of cleavage. 

 Excellent cutting angles have been obtained, too, in the case of stones 

 one face of which forms the outer coating, or skin as it is termed, of the 

 uncut gem. 



I always set or mount the diamond so that its cutting edge is 

 perfectly parallel with the line to be cut, and slightly raised in the 



