106 REPORT — 1855. 



ordnance might, with careful management, be introduced ; and assuming 

 that this could be done, we have the less hesitation in recommending it to 

 the attention of the Government as eminently entitled to a further extension 

 of experimental research. 



If casting in chill were successfully accomplished, artillery would be cast 

 on accurately turned and perfectly true mandrils, so as to chill or case- 

 harden the interior to a depth of about a tenth of an inch. This process 

 would consolidate the metal by a uniform rate of cooling, and entirely 

 disiiense with boring. In the attainment of these objects, it must, however, 

 be admitted that many difficulties have to be encountered, such as the 

 cooling of so large a mass of fluid metal without injuring the mandril, and 

 regulating the temperature so as to produce the desired chill. These are points 

 which require minute attention, and must be left to the consideration of the 

 Government and to the unerring test of experiment. 



In addition to the numerous suggestions contained in this Report, we 

 may state that experiments are now in progress to ascertain the strength 

 and other properties of a compound similar to meteoric iron, composed of 

 an alloy of about 2J per cent, of nickel melted with the best cold-blast 

 iron. His Grace the Duke of Argyll has kindly sent a quantity of cal- 

 cined nickel in order to ascertain the properties of this compound as 

 compared with those of the ordinary mixtures of the best metals. These 

 experiments are not yet complete ; but assuming the properties of the 

 mixture to be similar to those of meteoric iron, we should then have a strong 

 and very elastic material for the manufacture of artillery*. 



Mr. Joseph Whitworth, in a communication to the Committee, dated 

 September 20, 1855, refers to a rifled cannon, which he is constructing in 

 parts. It consists of three cast- or wrought-iron pieces bound together by 

 wrought-iron rings. The bore is nine-sided, with the requisite pitch for 

 imparting rotatory motion to the ball. 



Mr. Fulton, in a communication to the Committee, dated Glasgow, Sep- 

 tember 29, 1855, off'ers to undertake the forging of a wrought-iron gun 

 similar to Mr. Nasmyth's, and sends sketches of some very large forgings he 

 is making for Messrs. Scott Russell and Co.'s great vessel, showing what he is 

 able to accomplish : — 



tons cwt. qrs. 

 Paddle shafts, supposed to be ... 30 each. 



Propeller shaft, supposed 37 



Intermediate shaft, forged 28 13 1 



Crank, forged 10 10 2 



Crank, finished 7 4 



Friction strap, supposed 10 



Extracts from a letter addressed to the Committee by Mr. Macquorn Ran- 

 kine, dated Glasgow, November 13, 1855. 

 Mr. Rankine, after referring to the fact that it is extremely difficult to 

 break a brittle earthenware jar if filled with honey, the difficulty obviously 

 arising from the softness and defective elasticity of the honey, which im- 

 pedes the transmission of molecular vibrations, proposes to imbed the cannon 

 in a thick coating of some soft inelastic metal such as lead. 



* Since the above was written, several alloys of nickel and iron have been put to the 

 test of experiment, and have not proved so satisfactory in their powers of resistance to strain 

 and impact as was originally expected. 



