142 TKANSACTIONS OF THE CANADIAN INSTITUTK. [VoL. 1. 



platinum. Platinum does not melt even in the highest temperatnre 

 obtainable in a blast furnace, but only in the flame of the oxyhydrogen 

 blowpipe, and the calorific intensity of oxygen burned in hydrogen 

 = 3,I54°C. Now if we take for granted that the heat absorbed by the 

 nitrogen of the air is equal to the extra heat generated by the blast 

 caused by the forcing of the gases through the nozzle, which consequently 

 causes a more rapid combustion, hence a higher temperature, these figures 

 represent the blowpipe flames' temperature, hence the melting point of 

 platinum. Those calculations of mine are not mathematically correct to 

 the fraction of a degree or so but are quite accurate enough for our pur- 

 pose. Now the melting point of lead added to that of platinum = 3479, 

 therefore the mean = iy^g°C. I have melted such an alloy at iooo°C, 

 that is 739°C below the mean ; is this not a magnificent example ? This 

 law is confined to no special one but holds good for all alloys. 



Why, then, if this is a general law of alloys, is it not applicable in the 

 case of arsenic, sulphur, silver, and gold ? You will object that arsenic 

 and sulphur are not metals proper. That is quite true of the sulphur 

 but not so of the arsenic ; but still that would not incapacitate them to 

 form alloys with the metals. They may either be as a salt, such as a 

 sulphide or arsenide, or be in molecular proportion to form chemical 

 compounds, or in excess or deficient for such, and only form mechanical 

 mixtures, or one contained in solution in another, or in an allotropic 

 state ; but still they are alloys and in proof of this we have only to look 

 at shot lead, which is an alloy of arsenic and lead ; copper also alloys 

 with arsenic as a greyish brittle metal ; and has not galena the resemblance 

 and properties of an alloy ? 



In consideration of this I hold that arsenic, sulphur, silver and gold 

 do alloy and that therefore the temperature at which they melt is lowered 

 in virtue of their being alloyed with the sulphur and arsenic. 



In accordance with this, we will now consider the following data : — 



As — melts at 220°C. We will say that although it oxidises at that 



temperature, therefore its melting point 

 must be lower. 



S — melts at II5°C. 



Au— " iio2°C. 



Their sum is 1,437, their mean, 479°C ; therefore this would seem to in- 

 dicate the melting point of this alloy. This corresponds to a temperature 

 below incipient red, as it is according to Pouillett 525°C, dull red being 

 700°C. I do not mean to insinuate that gold alloyed with arsenic and 

 sulphur will be reduced to such a ridiculously low melting point, but I do 



