Mr. Fairbairn on the Strength of Alloys of Nickel and Iron. 487 



From the above there appears to be a loss of 22 to 26 per cent, as 

 compared with the Blaenavon No. 3 iron ; and in the next series of 

 experiments made upon similar mixtures, but with perfectly pure 

 nickel, the same indications of loss are apparent, but not to the same 

 extent as in the preceding, as may be seen from the following 

 results : — 



Taking the mean of these experiments, it will be observed that 

 the loss of strength is not so great as in the former, it being about 

 17 percent., or as 100:83. In the deflections and the power to 

 resist impact, they are, however, inferior to those first experimented 

 upon, as may be seen by the numbers, in the ratio of 465 : 280. 

 This in some degree neutralizes the measure of strength, by a pro- 

 portionate diminution of elasticity of the bars employed in the last 

 experiments. 



At the commencement of the paper, the author stated that the 

 experiments were undertaken for the purpose of ascertaining how far, 

 and to what extent, an admixture of nickel would improve cast iron ; 

 and that that improvement had reference, independent of other 

 objects, to increased tenacity in the metal employed for the casting 

 of mortars and heavy ordnance. 



During the last two years innumerable tests and experiments have 

 been made for that purpose with more or less success ; but the ulti- 

 mate result appeared to be, in the opinion of the author and others, 

 that for the casting, or rather the construction, of heavy artil- 

 lery, there is no metal so well calculated to resist the action of gun- 

 powder as a perfectly homogeneous mass of the best and purest cast 

 iron when freed from sulphur and phosphorus. 



In the discussion which followed the reading of the paper, Mr. 

 Calvert said that it was highly probable that nickel caused the in- 

 creased brittleness of cast iron, just as carbon, phosphorus, and sul- 

 phur, but that the result with malleable iron might probably be 

 very different ; and as meteoric iron is malleable, the trial could only 

 be complete when soft iron and nickel were united ; nevertheless 

 these experiments, as far as cast iron is concerned, were decidedly 

 new and of great value. 



