SCIENCE AND PROGRESS 



their obscure history be unveiled, would reveal any 

 striking difference. 



Whence come, then, the great strides of the last 

 ten or twelve generations? Many answers have 

 been given, but the subject seems to have engaged 

 chiefly men whose minds run to fine phrases or 

 metaphysical subtleties. The cause may be sum- 

 med up in a word: the invention and use of me- 

 chanical appliances. 



The phrase is used broadly. Under mechanical 

 appliances I include all that may contribute to ex- 

 act measurement and to the extension of our primi- 

 tive senses in any direction whatsoever. In this 

 sense the calculus or the reactions of the chemists' 

 test-tube must be reckoned as mechanical no less 

 than the thermometer, the microscope, or the bal- 

 ance. I would include even such aids to calcula- 

 tion as the use of the zero, or cipher, algebra, the 

 inventions of fluxions, logarithms, and the slide 

 rule. The balance must have been known from the 

 remotest ages, and some crude form of thermometer 

 must have come with the very beginning of metal- 

 lurgy, in the Bronze Age. But an accurate heat- 

 scale dates only from the time of Galileo. Strange 

 as it may seem, the use of the zero or, more strict- 

 ly, a decimal system of counting was not general 

 in Christendom before the fourteenth century. It 

 came to us from the Arabs, who in turn borrowed it 



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