NOVEHBEK 22, 1907] 



SCIENCE 



713 



disheartened by the failure and for the two 

 years and a half following he worked con- 

 tinuously, building new furnaces and tear- 

 ing them down, until he finally solved the 

 difficulty. It was found possible to deter- 

 mine when the burning out of the carbon 

 in the iron was practically complete by 

 watching the flame as it issued from the 

 converter. Then, by adding the right 

 amount of an iron containing manganese 

 and carbon, the proper composition for 

 steel could be secured. When Bessemer 

 tried again to introduce his perfected 

 process he met with a very cold reception 

 from the manufacturers. They said they 

 were not to be deceived a second time. He 

 was finally compelled to build works and 

 establish the manufacture for himself. He 

 succeeded beyond the most sanguine ex- 

 pectations, and the revolution in the manu- 

 facture of steel which dates from that time 

 is common knowledge. 



Agriculture still remains the most im- 

 portant industry in the world. From the 

 time that primitive man began to till the 

 soil to the middle of the nineteenth cen- 

 tury the farmer received but little aid from 

 chemistry. The work of the last seventy 

 years has changed all that. As late as 

 1840, it was generally supposed that plants 

 grew chiefly from the vegetable humus in 

 the soil. Many of the fundamental facts 

 on which to base a more correct view had 

 been known long before, but it was Liebig 

 who first grouped these facts together and 

 pointed out clearly that plants are 

 nourished by the inorganic constituents of 

 the air and soil and that it is the potash 

 and lime and phosphorus and inorganic 

 nitrogen of the soil which are vitally 

 essential to their growth. On this simple 

 foundation has grown up our great modern 

 fertilizer industry, which brings to our 

 farmers the phosphates from the seuth, the 

 potash salts from Germany, and the 

 nitrates from South America. The supply 



of the last is limited in consideration of the 

 present demand, and there has been a good 

 deal of speculation as to what our farmers 

 will do when the beds of nitrates are ex- 

 hausted. There is plenty of nitrogen all 

 about us in the air, however, and several 

 methods have already been developed for 

 utilizing this inexhaustible supply. 



I might speak further of the part that 

 chemistry plays, to-day, in the making of 

 paper, in the tanning of leather, in the 

 boiling of soap, in the manufacture of 

 glass, in making paints and varnishes and 

 india rubber, in the making of cement and 

 in the refining of petroleum, but I will not 

 take your time with further details. In 

 these and in many other industries the 

 work of the chemist has become an in- 

 dispensable factor. Fifty years ago there 

 were very few chemists in America and 

 those few were almost exclusively engaged 

 in teaching. To-day it is estimated that 

 there are 8,000 chemists in the United 

 States and a very large proportion of these 

 are employed in industrial work. But it 

 is not in technical lines only that great ad- 

 vances in chemistry have been made. I be- 

 lieve the advance which has been made in 

 chemical research is of much greater im- 

 portance. I have spoken of the fact that 

 Liebig gave to his students the love of re- 

 search and that they acquired in his labora- 

 tory the power of individual initiative. In 

 many of the chemical laboratories of our 

 colleges and universities and technical 

 schools are to be found to-day earnest 

 workers who are seeking for new truths and 

 who inspire their students with the power 

 to think independently and to do original 

 work. Whether the student's life work is 

 to be in the field of pure science or in its 

 technical applications, this power is the 

 greatest gift that a teacher can impart. 



While the material advantages which 

 have come to us from chemistry are very 

 great and may be justly emphasized, its 



