130 INDUCTION. 



are not ultimate ; they depend on causes. So far as 

 the properties of a thing belong to its own nature, and 

 do not arise from some cause extrinsic to it, they are 

 always the same in the same Kind*. Take, for in- 

 stance, all simple substances and elementary powers ; 

 the only things of which we are certain that some at 

 least of the properties are really ultimate. Colour is 

 generally esteemed the most variable of all properties : 

 yet we do not find that sulphur is sometimes yellow 

 and sometimes white, or that it varies in colour at all, 

 except so far as colour is the effect of some extrinsic 

 cause, as of the sort of light thrown upon it, the me- 

 chanical arrangement of the particles, &c. (as after 

 fusion). We do not find that iron is sometimes fluid 

 and sometimes solid at the same temperature ; gold 

 sometimes malleable and sometimes brittle ; that 

 hydrogen will sometimes combine with oxygen and 

 sometimes not ; or the like. If from simple sub- 

 stances we pass to any of their definite compounds,, as 

 water, lime, or sulphuric acid, there is the same con- 

 stancy in their properties. When properties vary 

 from individual to individual, it is either in the case of 

 miscellaneous aggregations, such as atmospheric air 

 or rock, composed of heterogeneous substances, and 

 not constituting or belonging to any real Kind, or it is 

 in the case of organic beings. In them, indeed, there 

 is variability in a high degree. Animals of the same 

 species and race, human beings of the same age, sex, 

 and country, will be most different, for example, in 

 face and figure. But organized beings (from the 

 extreme complication of the laws by which they are 



* I do not here include among properties the accidents of quan- 

 tity and local position. Every one is aware that no distinctions of 

 Kind can be grounded upon these; and that they are incident 

 equally to things of different Kinds and to things of the same. 



