MECHANICS AXD USEFUL ARTS. 67 



barrels. The improvement consists in making the grooves of the 

 barrel of a form somewhat resembling the letter V in their transverse 

 section, that is to say, the bottom of a groove is formed by a single 

 alible, instead of bv two angles in the ordinary wav. The object of 



~ ^ %/ t/ 



the improvement is to make the patch, when inserted with the ball, 

 fill the grooves more tisihtlv than can be done bv the common grooves. 



o a * o 



The barrel, by the new grooves, is kept more clean, as each patch 

 cleans out the barrel completely in its course, and the explosive force 

 of the powder is more directly confined and exerted upon the bullet 

 than can be done in a barrel where the grooves are not so tightly 

 packed by the patch. Scientific American. 



COMMERCIAL STATISTICS OF GREAT BRITAIN. 



MR. BRAITHVTAIT POOLE, in a recent work, gives the following 

 interesting statistics of Great Britain. Pitt and Canning stated 

 the yearly production of the agricultural and mechanical interests of 

 Great Britain at an amount equal to the national debt ; but nobody 

 knew how thev made it out. The summarv of these statistics, how- 



* 



ever, prove that these great statesmen were right. 



Mr. Poole shows that the Railways of Great Britain have cost 240,- 

 000,000; the Canals, 26,000,000; and the Docks, 30,000,000. 



The Mercantile Marine consists of 35,000 vessels, 4,300,000 tons, 

 with 240,000 men ; and one vessel is lost on an average with every 

 tide. The "navy consists of 585 vessels, 570,000 tons, and 48,000 men. 

 Yachts, 250, and 23,000 tons. 



The ancient Britons knew only six primitive ores, from which 

 metals were produced ; whereas the present scientific generation use 

 fifty. The aggregate yield of minerals is equivalent in value to about 

 25,000,000 annually.' 



The agricultural produce of milk, meat, eggs, butter and cheese, is 

 3,000,000 tons, of the value of 50,000,000. "The ale, wine and spirits 

 consumed annually exceed 3,300,000 tons, and 54.000,000; while 

 sugar, tea and coffee scarcely reach 450,000 tons, and 2 7,000,000. The 

 Fisheries of Great Britain net 6,000,000, annually. In Manufac- 

 tures, the cotton, woolen, linen and silk altogether amount to 420,000 

 tons, and 95,000,000; while hardwares exhibit 360,000 tons, and 

 20,000,000 ; in addition to which 1,250 tons of pins and needles are 

 made yearly, worth "1,100,000. 



Earthenware, 100,000 tons, 350,000.000; glass, 58,000 tons, 

 1,600,000. The Gazette shows an average of four bankrupts daily 

 throughout England and Wales. 



TIN PLATES. 



TIN PLATES, thin plates of iron dipped into molten tin, which 

 covers the iron completely, are manufactured in South Wales and 

 Staffordshire, to the extent now of about 900,000 boxes annually = 

 56,000 tons, value 1,500,000; affording employment to upwards of 



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