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S den tific Intelligence . — A rts . 
which are to be met with in the tool-shops ; and with such his 
writing engraver has now much less difficulty in performing his 
work than before. This process of Mr Turrell’s, of hammer- 
hardening his gravers on the angular edges cold , may still ad- 
mit of improvement. If the gravers were to be heated to the 
tempering degree, at the time of hammering them, the condens- 
ing effect of the hammer would be much greater. Mr Turrell 
finds, that, after hammering his gravers a certain time, they 
yield a sharp ringing sound to the blows, very different to that 
which they afforded on his beginning to hammer them ; and that, 
after perceiving that sound, he does not find that the hammer 
exercises any further action upon them, in condensing them. 
Possibly a renewal of the heat may promote their further con- 
densation. — Gills Technical Repository , Noth 1825. 
53. Excellent Building Stone near to Elgin. — At a late meet- 
ing of the Directors of the Scottish National Mining Company, 
there were submitted to their attention, besides many interesting 
specimens of ores, &c., specimens of a sandstone from the Earl 
of Eyfe’s quarries, near to Elgin. The colour is a yellowish- 
white, and the substance and texture of the stone good. It was 
considered, and with justice, as one of the most beautiful and 
excellent stones in the country, and well deserving the attention 
of those architects who wish to conjoin in their material richness 
and beauty of colour with durability of substance. 
54. Remarks on the Cultivation of the Silk - Worm , by John 
Murray , F. R. S. fyc. — This little work contains a condensed 
view of the facts communicated to the public in the Treatise of 
Count Dandolo. Mr Murray, in making known these import- 
ant details, has it chiefly in view to invite our countrymen to in- 
troduce and cultivate silk in Great Britain. Those who are in- 
terested in this subject will find Mr Murray’s Essay worthy of 
their attention. 
55. Manufacture of a Paper which has the property of re- 
moving Rust from articles of Iron and Steel. — After having 
dried a certain quantity of pumice among live coals, and reduced 
it to powder, grind it with linseed oil varnish, and then dilute 
it with the same varnish, until it be thin enough to be laid upon 
paper with a pencil. To give this layer a yellow, black, or 
