408 Foreign and Miscellaneous Intelligence. 



zinc ; in Z T 6 the two stationary points coincide at 204 ; the relation 

 of the variable point corresponds with that of the other alloys. 



For the combinations of lead and bismuth, I found the fixed point 

 to be 129, and the coincidence of the two stationary points to take 

 place at L s B 4 ; in L B the variable point is at 146, and in L B 2 at 

 143, but this latter observation proved to be the result of a remark- 

 able accident ; viz., when the thermometer was examined, the ball 

 was found to be compressed to such an extent as to raise the quick- 

 silver in the tube by six degrees ; this had, no doubt, been caused by 

 the great expansion which bismuth undergoes when becoming solid, 

 and which is such as generally to break the thermometer when 

 immersed in fused bismuth, and left in it till it is completely solid. 



In the alloys of zinc and bismuth the fixed point was found to be 

 at 251 ; the proportion, at which the depression of the thermometer 

 is regular, could not be ascertained, but I conceive it constitutes an 

 alloy, in which the relative quantity of zinc is very small. 



It seems to follow from these combined observations, that whatever 

 the proportion of the two metals may be which are fused together, 

 an alloy is always produced, which is represented by a simple atomic 

 ratio (and which might perhaps be properly called the chemical alloy) ; 

 if the metals are combined in this proportion, the temperature of the 

 mass regularly decreases till it arrives at the fixed point, which, 

 under such circumstances, coincides with that at which the mass 

 becomes solid, and which is generally lower than that at which 

 either of the two simple metals solidify ; if, on the contrary, one of 

 the metals is in excess, the thermometer is rendered stationary at 

 some point above that at which the chemical alloy becomes solid ; 

 for, as that portion of the metal which is in excess becomes solid 

 before the chemical alloy, the latter derives from it the heat which 

 becomes free by the congelation of the former. This must of course 

 take place at a degree which will be the higher in the ratio of the 

 quantity of the metal in excess. Within more or less time after the 

 solidification of the metal in excess, the chemical alloy becomes also 

 solid, and causes the thermometer to be stationary, in consequence 

 of its latent heat becoming free : the latter is the fixed, the former 

 the variable stationary point. The correctness of this view is also 

 proved by the known fact, that if the mass in fusion is allowed to cool, 

 solidification does not take place simultaneously, but it always, in more 

 or less time, becomes of a mortar-like consistence ; whilst, if the 

 metals are fused in the proportion of the chemical alloy, the mixture 

 'will be found to become solid simultaneously, and almost in a moment. 



It appears that there are also ternary chemical alloys as well as 

 binary ones ; of the alloys of lead, tin, and bismuth, for instance, 

 one of the points at which the thermometer is fixed is 98 ; for the 

 ternary alloys seem to have two fixed points, neither of which, nor 

 the proportion of the metals in the chemical ternary alloys, I have 

 yet been able to ascertain*. 



* Poggendorf's Ann, der Physik und Chemie, 1830, p. 240, 



