ACCORDANCE OF QUANTITATIVE THEORIES, d-c. 191 



tion and comparison with theory, in detail, is far too great 

 for private inquirers to undertake. In meteorology, espe- 

 cially, an enormous waste of labour and money is taking 

 place, only a very small fraction of the results recorded 

 being ever used for the advancement of the science. For 

 one meteorologist like Quetelet, Dove, or Baxendell, who 

 devotes himself to the truly useful labour of reducing 

 other people's observations, there are hundreds who are 

 under the delusion that they are advancing science by 

 merely loading our book-shelves with numerical tables. 



Purely empirical measurements may often indeed have 

 a direct practical value, as when tables of the specific 

 gravity, or strength of materials, assist the engineer ; the 

 specific gravities of mixtures of water with acids, alcohols, 

 salts, &c., are useful in chemical manufactories, custom- 

 house guaging, &c. ; observations of rain-fall are requisite 

 for questions of water supply ; the refractive index of 

 various kinds of glass must be known in making achro- 

 matic lenses ; but in all such cases the use made of the 

 measurements is not scientific, but practical. It may pro- 

 bably be asserted with truth, that no number which 

 remains entirely isolated, and uncompared by theory with 

 other numbers, is of any really scientific value. Having 

 tried the tensile strength of a piece of iron in a particular 

 condition, we know what will be the strength of the same 

 kind of iron in a similar condition, provided we can ever 

 meet with that exact kind of iron again ; but we cannot 

 argue from piece to piece, or lay down any laws exactly 

 connecting the strength of iron with the quantity of its 

 impurities. 



It is to be feared that almost the whole bulk of statis- 

 tical numbers, whether commercial, vital, or moral, is at 

 present, and probably will long continue, of little scientific 

 value. 



