SCIENCE ADVANCES TO MEASUREMENT. V21 



employ. Space is measurable: hence Geometry. Force ; 

 and space are measurable : hence Statics. Time, force, and 

 space are measurable : hence Dynamics. The invention of 

 the barometer enabled men to extend the principles of me- 

 chanics to the atmosphere ; and Aerostatics existed. When 

 a thermometer was devised there arose a science of heat, 

 which was before impossible. Such of our sensations as we 

 have not yet found modes of measuring do not originate 

 sciences. We have no science of smells ; nor have we one 

 of tastes. We have a science of the relations of sounds 

 diifering in pitch, because we have discovered a way to 

 measure them ; but we have no science of sounds in respect 

 to their loudness or their H7nbre, because we have got no 

 measures of loudness and timbre. 



Obviously it is this reduction of the sensible phenomena 

 it represents, to relations of magnitude, which gives to any 

 division of knowledge its especially scientific character. 

 Originally men's knowledge of weights and forces was in 

 the same condition as their knowledge of smells and tastes 

 is now — a knowledge not extending beyond that given by 

 the unaided sensations ; and it remained so until weighing 

 instruments and dynamometers were invented. Before 

 there were hour-glasses and clepsydras^ most phenomena 

 could be estimated as to their durations and intervals, with 

 no greater precision than degrees of hardness can be esti- 

 mated by the fingers. Until a thermometric scale was con- 

 trived, men's judgments respecting relative amounts of 

 heat stood on the same footing with their present judg- 

 ments respecting relative amounts of sound. And as in 

 these initial stages, with no aids to observation, only the 

 roughest comparisons of cases could be made, and only the 

 most marked difierences perceived ; it is obvious that only 

 the most simple laws of dependence could be ascertained — 

 only those laws which being uncomplicated with others, 

 and not disturbed in their manifestations, required no nice- 

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