TEE CHEMIST IN CONSERVATION 301 



recovered tar are separated naphthalene, toluene and anthracene from 

 which are derived the brilliant coal-tar colors and many synthetic me- 

 dicinal compounds, also disinfectants and preservatives like carbolic and 

 benzoic acids. In Germany the coal coked so that the by-products could 

 be recovered was 30 per cent, in 1900 ; 82 per cent, in 1909. 



Our chemists are devising means to prevent the contamination of 

 the atmosphere by industrial wastes. Witness the Sulphur, Copper 

 and Iron Company at Ducktown, Tenn,, whose blast furnace gases 

 contain a high percentage of sulphur dioxide because of the abundance 

 of sulphur in the ores. Instead of, as formerly, allowing this to escape 

 to poison the surrounding vegetation it is caught and converted into 

 sulphuric acid. One hundred and sixty tons are produced daily, of high 

 purity ; a waste product has been converted into an article of commerce 

 for which there is a constant demand. 



In agriculture the general outlook is highly encouraging. True, 

 much time will pass before the agricultural chemist is estimated at his 

 real value, but even now the farmer is making use of his assistance and 

 asking for his aid with increasing frequency. He is learning that the 

 old " rule-of-thumb " methods are unprofitable, and when he is convinced 

 that science can more abundantly fill his purse, the end that we desire 

 is in sight. It is within the remembrance of most of us what a change 

 has taken place in Iowa, within the past fifteen or twenty years with 

 respect to fertilizers — the putting back into the bosom of mother 

 nature the nourishing elements of which our crops have deprived her. 

 Fortunately our farms are still exceptionally fertile and by scientific 

 treatment we of Iowa may not be reduced to that dependence upon 

 artificial plant food which is so painfully noticeable in New England 

 and other eastern states. But our pride in our soil should not lead us 

 to overlook our imperfections. When we know that our average wheat 

 crop is, for the country, only twelve to fifteen bushels to the acre, that 

 of England, the Netherlands and Denmark over twice that and that 

 on some of our experimental farms it runs up to seventy to eighty 

 bushels, it should make us pause for serious reflection. On the other 

 hand, if, as we are told, the average crop of the Romans was but four 

 to five bushels we can take courage and strive for better results. 



I have spoken of new means of getting nitrogen, one of the three 

 plant nutrients most apt to be deficient. A second, potassium, occurs 

 abundantly in feldspars in a ^comparatively insoluble form. Recent ex- 

 periments by chemists, however, indicate that through very fine grinding 

 the door is unlocked which will set it free in a form which the plant can 

 assimilate. For the third nutrient, phosphoric acid, we must probably 

 depend upon re-using that taken up by the plant or upon undeveloped 

 deposits. Happily, we have such ones. Announcement has just been 

 made by geologists of large phosphate beds in several of our western 



