ON THE SIGNIFICATION OF CHEMICAL TERMS. g3 



an aggregate can be imagiricd to he divided without decom- 

 position, are called integrant parts; but the parts into which Integrant and 

 it is divided by decomposition are called component parts p°™j'^"^"' 

 or principles." These definitions would-be clear and intel- 

 ligible to me, if the words I have put in italics were omit- 

 ted *; the sense affixed to integrant parts is better than that 

 of Chaptal, and is the same as the most correct modern 

 writers apply to integrant particles. But, after thus de- 

 fining the terms integrant parts, I do not find, that you 

 have again used them throughout the chapter. 



From the high encomiums, which several modern writers Bertb^et on 

 pass on Eerthollet*s researches into the laws of chemical j^j^y^ 

 affinity, I was induced to hope, that in a volume written 

 exclusively upon affinity by so able a hand, I should find 

 the terra particle clearly defined in the first page. I took 

 up the English translation, and read 37 pages without once 

 meeting with the word particle, or any other word of simi- 

 lar import. I was beginning to think, that the author in- 

 tended to abolish-'the old doctrine of bodies consisting of 

 extremely small parts bound together by a principle of co- 

 hesion, or affinity of aggregation, and to establish the one 

 that bodies consist entirely of cohesion, when in the open- 

 ing of the 5th article I road, " the cohesion of the mole- Molecul*. 

 culae of a body is due to the reciprocal affinity of thes^ 

 moleculce;*' the word moleculae did not again occur in the 

 volume to my cursory observation. In the same page 1 met 

 with the phrase integral parts, and afterward in the space 

 of 150 pages the words par^ and particle were observed in 

 about a dozen places. Whatever obscurity may be found 

 in Berthollet's researches then, they ^a not arise frocatht* 

 frequent use of the term particle, 



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* I do not know how Mr Dalton would understand the pas'^age, if 

 the words in iralics were omitted ; but they appear necessary, to exiress 

 the true meaning with precision. Suppose a single atom of sulphuric 

 \acid combines with a single atom of mineral alkali to form a particle yf 

 isulphate of soda, and a crystal to be formed by th« aggregation of such- 

 particlus: we cannot actually divide jt into these component parts, 

 Ihough we can imagine it so divided. The word imagivcd may be here 

 takert aa synonimous with the word conceived of "\h^ geumctors, and has 

 no^rccssary relation to operative or human practicabHHy. N. 



G a JDr. 



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