354 DISCOURSE ON THE STUDY 



observation we now possess, and employed them as 

 we employ them now ? 



(387.) In any enumeration of causes which have 

 contributed to the recent rapid advancement of 

 science, we must not forget the very important one 

 of improved and constantly improving means of 

 observation, both in instruments adapted for the 

 exact measurement of quantity, and in the general 

 convenience and well-judged adaptation to its pur- 

 poses, of every description of scientific apparatus. 

 In the actual state of science there are few observ- 

 ations which can be productive of any great advantage 

 but such as afford accurate measurement ; and an 

 increased refinement in this respect is constantly 

 called for. The degree of delicacy actually attained, 

 we will not say in the most elaborate works of the 

 highest art, but in such ordinary apparatus as every 

 observer may now command, is such as could not 

 have been arrived at unless in a state of the mecha- 

 nical arts, which in its turn (such is the mutual 

 re-action of cause and effect) requires for its existence 

 a very advanced state of science. What an im- 

 portant influence may be exercised over the progress 

 of a single branch of science by the invention of a 

 ready and convenient mode of executing a definite 

 measurement, and the construction and common 

 introduction of an instrument adapted for it cannot 

 be better exemplified than by the instance of the 

 reflecting goniometer. This simple, cheap, and 

 portable little instrument, has changed the face of 

 mineralogy, and given it all the characters of one 

 of the exact sciences. 



