25& Mr. Herapath on True Temperature, and the [Oct; 



lower temperature be brought into an atmosphere above the 

 degree of its melting temperature, the temperature of the solid 

 will gradually rise until it reaches the melting point. During 

 this gradual rise, little, or, perhaps, no liquefaction will take 

 place. As soon, however, as any part of the body has attained 

 this temperature, the least increase will cause a disunion in some 

 few of the particles. I say in some few of the particles; for it is 

 nearly impossible a disunion could take place in all, or a very 

 great number at once, even if the disunitable parts in each par- 

 ticle had precisely the same degree of adaptation, which is highly 

 improbable. There can indeed be no doubt but that some of 

 the particles, however similar we may imagine them, would part 

 with their disunitable parts at lower temperatures than others ; 

 and even if this were not the case, the temperature of the body 

 can hardly be mathematically uniform throughout the whole of 

 its extent. On either account, or indeed on both, a disunion 

 will take place in some few particles before it will in others. No 

 sooner, however, has this happened, but a diminution of temper- 

 ature in the immediate vicinity of the disunited particles 

 succeeds, because the same motions being by this division distri- 

 buted among a greater number of particles, each of them will 

 have a less motion after than before the disunion. But notwith- 

 standing a diminution of temperature, accurately speaking, will 

 follow a disunion, it will not affect the general temperature of the 

 body, nor even sensibly that of the regions in which it takes 

 place ; for the particles being exceedingly minute with respect 

 to any sensible space, and but a very small portion of them in any 

 space being disunited at once, the diminution of temperature is 

 but trifling when distributed among the surrounding particles, 

 and is rapidly made up by the superior temperature of the cir- 

 cumambient air ; on both of which accounts no sensible effect 

 can be produced on the thermometer or temperature of any 

 given space. As soon as this defect is made up, other disunions 

 und diminutions follow, which are again succeeded by like 

 phenomena, and so on until the whole solid is liquefied. During 

 all this time, it is evident that the temperature of the body, at 

 least in the immediate neighbourhood of the solid parts, remains 

 stationary, and cannot ascend above the point at which the least 

 particle of it would liquefy — a consequence that precisely accords 

 with pliaenomena. 



The same arguments manifestly apply with respect to the 

 fixity of the point of liquefaction and the invariability of the tem- 

 perature of the body during the process, whether the body be 

 large or small, and, therefore, likewise, whether it be one united 

 mass, or a congregation of several smaller ones. Consequently, 

 if a given weight of a solid in one mass require a given weight of 

 a fluid at a given excess of temperature just to liquefy the whole 

 of it, an equal weight of the same solid at the same temperature 

 pulverized will require the same w T eight of the same fluid with 



