LIFE of Dr HUT TON. 



79 



plain the phenomena of light, heat, and eleariclty. He confider- 

 ed all thefe three as modifications of the folar fubftance, and 

 thought that many of the appearances they exhibit, are only to 

 be explained, on the fuppofition that they confift of an expan- 

 five force, of which inertnefs is not predicable ; in particular, 

 that hght is a power propagated from the fun in all diredions,' 

 like gravity, with this difference, that it is repulfive, while gra- 

 vity is attraaive, and requires time for its tranfmiffion, which 

 the latter does not, at leaft in any fenfible quantity * 



The profecutionof this fubjed has led him to confiderthe nature 

 of PHLOGISTON, a fubftancc once fo famous in chemiftry, but of 

 which the name has almoft as entirely difappcared from the vo- 

 cabulary of that fcience, as the word Vortex from the language 

 of phyfical aftronomy. The new and important experiments 

 made on the calcination of metals, and on the compofition of 

 water, are, as is well known, the foundations of the antiphlogil 

 ftic theory. Nobody was more pleafed than Dr Hutton wfth 

 thefe experiments, nor held in higher eftimation the charader 

 and abilities of the chemifts and philofophers by whom they 

 were conduded. He was neverthelefs of opinion, that the con- 

 clufions drawn from them are not altogether unexceptionable, 

 nor deduced with a fufficient attention to every circumftance.' 

 This remark he thought pecuHarly applicable to what regards 

 the compofition of water, to the phenomena of which experi- 

 ment, the difi^brtation we are now fpeaking of is chiefly direded. 

 The two aeriform fluids, it is there obferved, which compofe 

 water, m order to unite, muft not Amply be brought together, 

 for in that ftate they might remain for ever unchanged, but they 

 muft be fet on fire, and made to burn, and from this burning 

 there are evidently two fubftances which make their efcape. 



Vol. v.— p. III. L 



namely, 



/ S« Diff«tation3 V. and VI. on Matter and Motion, in the work above quot- 

 ed. The Chemical DilTertation on Phlogiiloa is in the fame volume, £.17.. 



