XLIII.] CLASSIFICATION OF THE SCIENCES. 209 



On reading over this enumeration, the most natural and 

 probably the first remark of the reader will be that it 

 must be very incomplete, for it omits some of the most 

 important of the sciences. It has no place for astronomy. Position of 

 meteorology, or geology. This is true : the foregoing series '^^*'"°" 

 is not a complete enumeration ; it needs to be supple- meteoro- 

 mented by another series, containing astronomy, meteoro- a^\o^ j^ 

 logy, geology, and a few others. It is in the nature of ^"otlier 



S6riGS of 



things impossible to place all the sciences in a single series, sciences. 

 Every one of the sciences enumerated in the foregoing 

 tabular form has for its subject-matter a particular set of 

 natural laws ; and the tabular eniimeration is an attempt 

 at a classification of natural laws — a classification which 

 probably will be found to admit of improvements in detail, 

 though it is, I think, beyond doubt correct in principle. 

 But such a science as astronomy or geology has for its 

 subject-matter, not a particular set of laws, but a par- 

 ticular set of phenomena as actually found in nature. 

 Now, it is evident that a science whereof the subject- whereof 

 matter is a particular set of laws, and one whereof the ^^% ^^^' 

 subject-matter is a particular set of phenomena, cannot not Jaws 

 properly be placed in the same series. This distinction nomena' 

 would not be of any importance if each set of phenomena 

 as occurring in nature were due to only a single set of 

 laws : if, for instance, astronomy were exclusively an 

 application of dynamical laws, meteorology of the laws 

 of heat, and geology of the laws of chemistry and crys- 

 tallization. But such is not the case ; it is only approxi- 

 mately true of astronomy and meteorology, and is not true 

 of geology at all. Astronomy is no doubt chiefly dynamical ; 

 but if we admit — as I think we must — the nebular theory 

 as a legitimate branch of astronomy, it has to do also with 

 the laws of heat and of the physical constitution of gases and 

 vapours.^ The most important facts of meteorology depend 

 on the laws of heat, but some of them are electrical and 

 some are optical. And the facts of geology do not depend 



1 It may be said that the study of the sun's atmosphere also belongs 

 to astronomy, and yet it does not depend on dynamics. But it is better 

 to regard this as a part of meteorology. 



VOL. II. P • 



