366 Mr. R. Mallet on the alleged [June 11, 



III. "On the alleged Expansion in Volume of various Substances 

 in passing by Refrigeration from the state of Liquid Fusion 

 to that of Solidification." By ROBERT MALLET, C.E., F.R.S. 

 Received April 28, 1874. 



(Abstract.) 



Since the time of Reaumur it has been stated, with very various 

 degrees of evidence, that certain metals expand in volume at or near 

 their points of consolidation from fusion. Bismuth, cast iron, antimony, 

 silver, copper, and gold are amongst the number, and to these have 

 recently been added certain iron furnace-slags. Considerable physical 

 interest attaches to this subject from, the analogy of the alleged facts to 

 the well-known one that water expands between 39 F. and 32, at which 

 it becomes ice ; and a more extended interest has been given to it quite 

 recently by Messrs. Nasmyth and Carpenter having made the supposed 

 facts, more especially those relative to cast iron and to slags, the 

 foundation of their peculiar theory of lunar volcanic action as developed 

 in their work, ' The Moon as a Planet, as a World, and a Satellite' 

 (4to, London, 1874). There is considerable ground for believing that 

 bismuth does expand in volume at or near consolidation; but with 

 respect to all the other substances supposed to do likewise, it is the 

 object of this paper to show that the evidence is insufficient, and that 

 with respect to cast iron and to the basic silicates constituting iron 

 slags, the allegation of their expansion in volume, and therefore that 

 their density when molten is greater than when solid, is wholly 

 erroneous. The determination of the specific gravity, in the liquid 

 state, of a body having so high a fusing temperature as cast iron is 

 attended with many difficulties. By an indirect method, however, and 

 operating upon a sufficiently large scale, the author has been enabled to 

 make the determination with considerable accuracy. A conical vessel of 

 wrought iron of about 2 feet in depth and 1*5 foot diameter of base, aud 

 with an open neck of 6 inches in diameter, being formed, was accurately 

 weighed empty, and also when filled with water level to the brim ; the 

 weight of its contents in water, reduced to the specific gravity of distilled 

 water at 60 F., was thus obtained. The vessel being dried was now 

 filled to the brim with molten grey cast iron, additions of molten metal 

 being made to maintain the vessel full until it had attained its maximum 

 temperature (yellow heat in daylight) aud maximum capacity. The 

 vessel and its content of cast iron when cold were weighed again, and 

 thus the weight of the cast iron obtained. The capacity- of the vessel 

 when at a maximum was calculated by applying to its dimensions at 60 

 the expansion calculated from, the coefficient of linear dilatation, as given 

 by Laplace, Riemaun, aud others, and from its range of increased tem- 

 perature ; and the weight of distilled water held by the vessel thus ex- 



