280 BOTANICAL GAZETTE " [ocToBER 
the “nitrate-free method.” The details for these methods were as 
follows: . 
1. For the nitrate-free method——The material to be analyzed 
was first placed in the Kjeldahl flask. This material was either 
in the form of a solid, or in the case of solutions was evaporated 
nearly to dryness as hereafter described. Next, 10 gm. of a mix- 
ture of potassium sulphate and copper sulphate were added to 
the flask. The proportion of these which gave the best results was 
9.2 parts of K,SO, to 0.8 parts of CuSO,. Then 25 cc. of sulphuric 
acid was added, after which gentle heat was’ applied. This was 
increased gradually to strong heat and this was continued for 
15-30 minutes after clearing. The contents of the Kjeldahl flask 
were now rinsed into a tooo cc. distillation flask and diluted with 
240 CC. ammonia-free water. The whole was made alkaline by 
the addition of 120 cc. of a strong solution of sodium hydroxide 
40 gm. pure sticks to 120 cc. ammonia-free water). Two small 
Pieces of stick zinc (granulated zinc caused too much foaming) 
were now added, and then heat was applied until about 250 cc. 
of the distillate had passed over into the standard acid. The 
volume of the standard acid was in most cases 20 cc. 
2. Method in presence of nitrates.—The material was added to 
the digestion flask and when this was thoroughly cool, 30 cc. of a 
mixture of concentrated sulphuric acid and salicylic acid were 
added. In most cases these two, previously mixed, were added 
in the proportion of 1 gm. salicylic to 30 cc. sulphuric; but when 
large quantities of nitrate were present, 1 gm. of salicylic was 
used to 25 cc. sulphuric. The flask was now allowed to stan 
5~Io minutes with frequent shakings, and then 5 gm. sodium 
thiosulphate were slowly added and well mixed. Heat was then 
slowly applied for about 5 minutes or until white fumes began to 
appear, after which the whole was cooled for 5-10 minutes. Next, 
to gm. of a mixture of potassium sulphate and copper sulphate were 
added; gentle heat was applied till all foaming ceased, and lastly, 
Strong heat was applied till 15-30 minutes beyond clearing. Distil- 
lation was carried out as in the nitrate-free method. 
The titration method was used throughout for determining the 
quantity of ammonia in the distillate. For very small quantities 
