68 Maine Agricultural Experiment Station. 1920. 



cent of water. If they are exposed to a moist air they are like- 

 ly to take up water. If kept in a very dry place they will lose 

 water. For the most part there is a greater tendency to absorb 

 than to lose water. In the first instance the goods will increase 

 in weight and in the second lose in weight. In the specimen 

 table above the two samples B-i and B-2 are the same brand 

 from the same maker. Probably when they left the factory 

 they both carried about 9 per cent of water. One has prob- 

 ably lost and the other gained about 2 per cent of water. A 

 sample carrying less than 9 per cent of water will likely over- 

 run its guaranteed analysis and a sample containing much more 

 than 9 per cent of water is likely to fall short in one or more 

 constituents. It is unfortunate that the difficulty of transport- 

 ing suitable accurate scales from one place to another prevents 

 the inspector actually weighing the packages from which his 

 samples are drawn. No one thing would add more of value to 

 fertilizer inspection than the actual weighing of packages which 

 are sampled. 



If the weight of the goods at time of sampling as compared 

 with the claimed weight was known a simple calculation would 

 show the actual content of the fertilizer when it left the factory. 

 When the sample is taken it is at once put into a tightly sealed 

 jar and kept sealed until the analysis is made. So the column 

 headed water indicates the amount carried at the time the in- 

 spector drew the sample. It will be noted that samples A and 

 C carry about 9 per cent of water as do the majority of sam- 

 ples examined. In considering the actual reported analysis due 

 regard should be given to the amount of water the goods carry. 



Nitrogen. The nitrogen may be present as mineral or or- 

 ganic or both mineral and organic. The mineral nitrogen will 

 be present as a nitrate (usually nitrate of soda with more or 

 less nitrate of potash) or as an ammonia salt, usually the sul- 

 phte of ammonia. 



That one is not sure of. getting the same amounts of dif- 

 ferent forms of nitrogen in different lots of the same brand is 

 illustrated by B-i and B-2 above, which are two samples from 

 different lots of the same kind of goods. While they agree 

 closely in the total mineral nitrogen, 2.07 per cent in B-i and 

 2.08 per cent in B-2, B-i carries only .57 per cent as nitrate 

 while B-2 has 1.32 per cent. And B-i has 1.50 per cent nitro- 

 gen as ammonia and B-2 only .76 per cent. 



