93 
MINUTES OF PROCEEDINGS OF 
The last shows a considerable inprovement over the others, being due to a 
great extent to the fact that a sifting apparatus, of the nature described, was 
now erected on the machine, so as to sift the pebbles rather severely, by 
taking out all the small and flakey specimens. This materially reduced the 
per-centage of finished pebbles obtained from it; that, however, is not to be 
considered in comparison to the improvement produced in the powder. 
The author had all along been favourable to the principle of the other 
machine, proposed by Captain Smith, and had for some time, after a good 
deal of trouble and contrivance, got a design ready by which the strips could 
be conveyed from the first to the second pair of rollers. When Colonel 
Younghusband found, therefore, that the per-centage of pebbles produced with 
his machine was only about 60 per cent., he ordered an experimental machine 
to be made according to this design. Tig. 8 will show its working. 
It will be observed that the difficulty consists in conveying the strips, 
which fall in regular succession, from the first to the second pair of rollers, 
so that they not only shall not inconvenience each other, but also shall change 
their direction from moving sideways to a motion endways. This is ac¬ 
complished by allowing the strips to fall upon a board, over which a 
succession of strips of wood are moving sideways, and scraping along the 
surface. Each strip falls into a space between two strips of wood, and is 
carried sideways along the board. When the first strip gets to the end of 
the board, it drops over on to a band passing below in a direction at right 
angles, and is thus conveyed endways to the second pair of rollers. It is 
manifest, if the board remain stationary, the second strip will drop over on to the 
top of the first before it has time to clear out of the way. To prevent this, the 
board is made to move backwards so that the second strip, instead of falling 
on to the top of the first, falls alongside it, and slightly in ar'rear, and so on w 
with the next and the next, till the board has moved as far back as can be 
allowed. The direction of the board is then suddenly changed, and it moves , 
Fig. 8. Scale 
forward in the direction of the strips of wood and at the same rate, so as to form a 
false bottom to the compartments which contain the strips of powder. When 
