188 NATURE STUDY REVIEW [10:5— May, 1914 



whose blossom has faded, and bring in fresh blossoming plants 

 from the growing room. These are arranged by the girls to give 

 the best effect they can obtain. In the workroom they mix the 

 soil, sand, loam and fertilizer in which to plant their seed. Each 

 girl prepares her own flat, puts in the seeds, marks her flat with her 

 own label and puts the flat away. There is just time left to put 

 the tools away. The greenhouse day is over. 



The article on Studies of Commercial Fertilizers by B. M. 

 Davis in the April nimiber should be corrected as follows : 



1 142.8 on page 127 should be 1 142.5. 



Last two paragraphs on page 127 and second on page 128 should 

 read as follows: 



At $57.50 per ton, one pound of nitrate of soda will cost 2.875 

 cents (57.50 X 100 -^ 2000 = 2.875). 500 pounds will cost 

 $14,375 (500 X .02875 = 14.375)- 



At $16 per ton, one pound of acid phosphate will cost .8 of a cent 

 (16 X 100 -f- 2000 = .8). 1 142.5 pounds will cost $9.14 (i 142.5 X 

 .008 = 9.14). 



The total cost of materials to prepare one ton of 4-8-3 fertilizer 

 will be $26,035 (14-375 + 9-14 + 2.52 = 26.035). The total 

 niunber of pounds of these materials needed to make a ton of a 

 4-8-3 fertilizer will be 1762.5. Therefore, 237.5 pounds of filler 

 must be added to bring the mixture up to 2000 pounds (2000 — 

 1762.5 = 237.5). In farm practice, however, the fertilizer may be 

 applied at a correspondingly lower rate per acre. In this case 

 about seven-eighths of the full amount per acre should be supplied 

 thus saving the trouble of adding a filler. 



