HISTORY OF SCIENCE 37 



A chemical discovery can revolutionize a whole country, just 

 as completely as a geological one; as soon as it becomes possible 

 to realize, on a business basis, the chemical synthesis of a natural 

 product (like indigo, vanilla, India rubber), the agricultural in- 

 dustry and civilization of immense countries are in danger. 



Technical inventions are more precisely determined every day 

 by industrial needs. The manufacturer can often say very defi- 

 nitely to the inventor: "This is the invention which I now need 

 to improve my production." Besides, every invention starts a 

 series of others that the first has made necessary and that it would 

 have been impossible to realize, or even to conceive, previously. 



Lastly, commercial needs also influence the development of the 

 sciences, not only the natural sciences and geography (that is too 

 obvious to dwell upon), but even mathematics. It is necessary 

 to take into account the evolution of book-keeping and banking 

 business to understand thoroughly the introduction and the spread 

 of Hindu- Arabic numerals into Europe, and later the invention of 

 decimal fractions. It is also owing in great measure to commercial 

 requirements that many astronomical discoveries were made, and 

 that the different systems of weights and measures were created. 



3. Science and Religion. Science and religion have never ceased 

 to influence one another, even in our own time and in the coun- 

 tries where science has reached a high degree of perfection and in- 

 dependence. But of course the younger science was, and the farther 

 we go back through the ages, the more numerous these inter- 

 actions are. Primitive people cannot separate scientific or technical 

 ideas from religious ones, or, more exactly, this classification has 

 no sense to them. Later, when the division of labor had created 

 some scientists or engineers, distinct from the priests, or at least 

 had given birth to a class of priests who had undergone a higher 

 scientific training than their colleagues, even then the interpreta- 

 tion of the holy books, the observance of rites, the needs of agri- 

 culture and medicine, the making of the calendar, and above all, 

 the hopes, the fears and the anxieties of a very precarious exist- 



