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Scientific Intelligence. — A ris. 
29* On improving Bricklayers ’ Trowels , hammer -harden- 
ing them ; by Mr Wdlby. — There is not, perhaps, an implement 
that undergoes more severe treatment than this, in its constant 
employment of hacking bricks into shape, and thus encounter- 
ing the pieces of flint, pebbles, &c. ordinarily mixed with the 
clay ; and which, besides having a tendency to injure its 
edges, also render it liable to break continually. Mr George 
Walby, therefore, by his excellent processes, accomplished a 
most difficult task, and rendered his trowels highly prized, by 
those who were the most competent j udges of their merit, from 
their constant experience in their use. They were made of the 
best shear-steel, carefully worked throughout, and especially to 
avoid over heating the steel ; and towards their finishing in the 
plating or forging, and when nearly reduced to their proper 
thickness, besides heating them in a clean hollow fire, to avoid 
contact with cinders, &c. ; he also removed all scales upon their 
surface, previous to giving them their last polishing, under 
the rapid blows of a hammer driven by a steam-engine, by means 
of a very ingenious revolving elastic steel-brush of his invention. 
He carefully attended to the proper hardening heat, and 
quenched them in a composition or hardening liquor, similar to 
those used by saw-makers ; he next blazed them off to the 
spring temper, and, lastly, hammer-hardened them as much as 
possible. They were then ready for grinding ; after which ope- 
ration, their elasticity being again restored by blueing them, 
they were glazed or brightened, ready to be mounted into their 
handles. — GUIs Technical Repository. 
30. On improving Brills by hammer-hardening them cold.— Mr 
Andrew Pritchard, the inventor of the hard shell-lac cement, find- 
ing that steel, when hardened and tempered, is susceptible of 
receiving the condensing effect of the hammer, has applied it, 
with considerable advantage, to the points of small drills, by 
hammering them upon their flat surfaces. 
31. On the improvement of Square Broaches or Boring-bits.—™ 
Mr Joseph Clement, an excellent workman and mechanical 
draughtsman, informed Mr Gill, that a friend of his in Scotland, 
many years since, improved the quality of his square broaches, 
by hammer-hardening them cold, after being hardened and tem- 
pered upon their flat sides. Mr Gill thinks it would have been 
