23 

 CHEMICAL PRODUCTS. 



103. Specimens of Prussian Blue and of large Crystals of 

 Prussiate of Potash.— Thomas Bramwell, Esq., Newcastle.— -^ 

 The quantity of these substances manufactured by the sole \^ 

 maker on the Tyne is about 110 tons a year. The average price 

 is one shilling and a penny per pound— total value, .£'24,640. 

 In 1828 the average price was 5s. per pound. 



104. Specimens illustrating the action of the preserving 

 substance employed in Kyan's patent process. — Deposited by 

 Richard Fell.— These specimens of fir pit props and calico bags, 

 containing pieces of No. 2 canvas, cordage and twine, prepared 

 according to the patent process, together with unprepared 

 articles of the same description, which had been respectively 

 exposed for a lengthened period of time to the same destructive 



agents. 



105. Specimens of Leather, and Model of a Machine, illus- 

 trating a new mode of Tanning.— By William Herapath, Esq. 

 Bristol. — For an account of this important improvement in the 

 art of tanning see the Mechanics' Magazine for April, 1828. 



Action of Water on Herapath's Patent Leather. 



jj/Sy^^^^^^^B On thick sole after five hours. 

 Do after nine hours. 



On thin sole after nine hours. 



106. Large Crystals of Alum and Soda.— Yrom John Lee 

 and Co.— The quantity of Soda annually manufactured on the 

 Tyne amounts at present to about 20,000 tons of crystalized at 

 ^11, and 10,000 of dry at ^15 per ton— total value ^370,000. 

 The price of the two varieties in 1828 was ^£'20 and £^5 respec- 

 tively. Of Alum about 2,000 tons are manufactured by the 

 direct action of Sulphuric Acid on clay. The present price is 

 £\0 per ton. 



