Scientific Intelligence. — Arts. 373 
engraving, which required particular accuracy in their construc- 
tion. He was in the habit of finishing his turning-tools for brass, 
after forming them into shape, and whetting them, by burnishing 
their edges from their sides toward their flat faces, and thus gi- 
ving them a hardness and smoothness not to be acquired in any 
other way ; and, in fact, they polished the brass- work turned by 
them. The last instance is borrowed from the practice of a late 
eminent mechanic in this country. He was employed to make 
some hardened and tempered steel-cutters for an engine, and 
which were to be driven with great velocity by a steam-engine 
at Manchester, for a cotton-mill there, to cut brass-toothed 
wheels and pinions, they requiring to be cut, rounded off, and 
polished at once. After properly shaping them, and skive-grind- 
ing the faces of their teeth, he finished them by burnishing their 
edges from their sides to their flat faces ; and their effects in 
cutting and polishing the teeth at once were truly wonderful. — 
The currier's shaving-knife is a two-edged instrument, about 
S\ or 4 inches broad, 14 inches long in the blade, and half an 
inch thick in its middle part, gradually tapering away from 
thence to its edges. It has two handles, one in the direction of 
the blade, and the other at right angles to it. It requires to be 
made of excellent^ steel, and to be well tempered; and, indeed, 
there are but very few makers of repute in this country. When 
the edge requires grinding and whetting, the former of these 
operations is performed upon a flat rub-stone, similar to what 
carpenters sharpen their plane-irons on, with the application of 
water. This stone is about 6 inches broad and 18 inches long ; 
and, so very careful are they to keep its surface flat, that it is a 
regulation in the work-shops, for every workman, after using 
the stone, to write his name upon it with a piece of coal ; when, 
if his successor finds it left so uneven that a halfpenny can be 
passed underneath the edge of an iron laid upon it, the former 
workman is subjected to a fine for his carelessness. After being 
carefully ground upon this stone, it is whetted upon a flat circu- 
lar piece of Welsh or Scotch blue-stone, about 8 inches in dia- 
meter ; likewise with the application of water, carefully preserv- 
ing the edges straight. The edges are then ready to receive the 
effect of the burnisher upon them, to turn them to the two op- 
posite sides, and fit them for use. The burnisher consists of a 
