392 Miscellanies. 



We purpose, from time to time, keeping our readers informed 

 on any new and valuable works whicli may hereafter be published, 

 and also of such instruments and accessories as may be helpful- 

 to microscopie observation. We invite communications from those 

 of them who arfe original observers, and will be happy to affoid 

 such information, advice, or assistance as may at any time be in 

 our power. 



SCIENCE AND THE INDUSTRIAL ARTS. 



Manufacture of Iron in Great Britain. Little more than 

 one hundred years ago, the quantity of iron made in the kingdom 

 of Great Britain was about twenty -five thousand tons, and at the 

 beginning of this century one hundred and seventy thousand tons. 

 Fifteen years ago this quantity had increased to one and a half 

 millions of tons, and at present the production reaches, or exceeds 

 two and a half millions of tons. 



Propeller Shaft Bearings. — An English engineer has origi- 

 nated a novel plan for the construction of plummer blocks, or 

 bearings for shafts, particularly under circumstances where high 

 velocities are required, such as screw propeller shafts. The plan 

 consists in surrounding the journals of the shaft with brass casings. 

 The inner surface of the bearings is grooved, to receive fillets of 

 wood which project beyond the inner surface, like cogs to a wheel, 

 so as to prevent the shaft coming in contact with the metal. 

 Through the spaces formed between the fillets water is allowed 

 to flow freely between the "shafts and the bearings, keeping the 

 whole cool, and acting as a' lubricator. — Another modification of 

 the invention is to fix the wooden fillets on the shaft, which then 

 rotate with it in the brass bearings. The wood prepared for the 

 purpose is lignumvitge, which is found so well to withstand friction 

 in machinery. 



Lightning Rods Attracting Lightning. — Sir Snow Harris has 

 made a valuable scientific report to Parhament, in which he 

 refutes the fallacy of the unphilosophical assumption that lightning 

 rods " attract " the lightning, and so act as efiicieut safeguards. 

 It is proved by an extensive induction of facts, and a large gene- 

 ralization in the application of metallic conductors, that metallic 

 substances have not exclusively in themselves any more attractive 

 influence for the agency of lightning than other kinds of common 



