524 EXPERIMENT STATION RECORD. [Vol.37 



The statistics for production of sulpliate of ammonia during 1916 are vei'y 

 incomplete. The production in Great Britain and Ireland from all sources in 

 that year was 445,029 tons, of which 263,4T3 tons was exported. The production 

 in the United States was 294,835 tons, as compared with 199.571 tons in 1915. 

 Of this amount, 246,754 tons was obtained from coke ovens and 48,081 tons from 

 gas and carbonizing works. The United States imported 13.170 tons of sulphate 

 of ammonia during the year. The average price of sulphate of ammonia in 

 New York for 1916 was $83.86 per metric ton. Incomplete statistics show that 

 synthetic nitrogen compounds were exported during the year by Norway to 

 the extent of 82.276 tons. 



As regards fertilizers in general, the statistics since the beginning of the 

 war are very Incomplete. In general, an Increasing demand prior to the war 

 was evident In Russia, Japan, South Africa, Australia, and Hawaii, with an 

 inadequate supply since that date. Among other products useful to agriculture 

 for which statistics are given are sulphur and copper sulphate. 



An extensive bibliography of recent literature on fertilizers and chemical 

 products useful for agriculture is given as usual. 



Fertilizer analyses, A. J. Pattkn, E. F. Bergeb, A. E. Smoix, and E. A. 

 DeWindt (Michigan Sta. Tiul. 27S (1016), pp. 5-5/).— This bulletin contains the 

 results of actual and guaranteed analyses of 549 samples of fertilizers and 

 fertilizing materials collected for inspection in Michigan during 1916. It was 

 found that of the 549 samples "30 (5.5 per cent) are below guarantee in 

 nitrogen, 38 (6.9 per cent) are below in available phosphoric acid, 6 (1 per 

 cent) in total phosphoric acid, and 23 (4.2 per cent) in potash." 



AGRICULTURAL BOTANY. 



Department of botanical research, D. T. MacDougal (Carnegie InM. Wash- 

 ington Year Hook, 15 (1916), pp. 51-9.5). — A summary is given of the more im- 

 portant results as condensed from the reports by the several Investigators tak- 

 ing part in the various phases of botanical work. The groupings under which 

 the work is reported include photosynthesis, imbibition, and growth ; ecolog>- and 

 phytogeography ; genetics and taxonomy ; eremography ; equipment ; and field 

 work. 



It is stated that the study of the available facts and accepted conclusions 

 regarding photosynthesis eliminates the theory of Baeyer from the possible 

 explanations. The Initial stage is probably much more complex than a simple 

 condensation of formaldehyde to sugar. A study of the cacti regarding the 

 carbohydrate economy of plants yields no evidence of special formative sub- 

 stances. Sugar starvation may occur as a result of desiccation or of enzym- 

 inhlblting temperatures even when plenty of starch is present. 



The lower temperature limit of growth in a single plant may range from 

 10 to 25* C. and the upper from 26 to 43', with a maximum ftf 49° for growth 

 and as high as 53° for endurance. Temperature coefficients of 2 or more for 

 every rise of 10° were found between 10 and 30 or 35°. AH temperatures were 

 those of the plant body Itself, which may be as much as 8 to 9° above that of 

 the surrounding air. 



The precision auxograph now in use indicates reliably an increase or decrease 

 in length or thickness to within 0.0004 in. No inhibiting effect of light on growth 

 of Eriogonum nudum was shown, the maximum occurring in daylight and the 

 rate depending largely upon the balance between absorption and water loss. 

 Imbibition, defined as distensive force in the earlier growth of the cell, plays 

 an important but diminishing part as vacuoles form and the protoplast enlarges, 

 osmosis meanwhile increasing in importance. Acidity checks growth, most 



