196 MAINi; AGRICULTURAL IJXPERIMENT STATION. I906. 



it is difficulty to so completely powder it and thoroughly incor- 

 porate it in the goods that the sample drawn in the inspector's 

 tube shall have its just amount — neither too much nor yet too 

 little. To try to meet this difficulty, the samples are taken from 

 a large number of packages and the final sub-sample is taken 

 with the greatest care. It is because of the difficulty of accu- 

 rate sampling of fertilizers that the Station only undertakes the 

 analysis of samples taken by its inspector, and employs an 

 experienced chemist who from his laboratory experience fully 

 recognizes the importance and difficulties of correct sampling. 



It is only fair to the manufacturers to say that probably no 

 class of goods are more nearly sold on their merits than are 

 commercial fertilizers. So far as the writer knows, there has 

 not been a case in 10 years that could be called a wilful attempt 

 on the part of a maker of fertilizers sold in Maine to defraud. 



THE COMPARISON 01^ STATION ANALYSES FOR THREE YEARS. 



It is important that the purchaser of fertilizers should know 

 the analyses not merely for the current year but as a guide for 

 future purchase to know how they have run for several years. 

 The tables on pages 178 and following of this bulletin, show how 

 the samples collected by the Station inspector in 1906 compare 

 with the guarantees. The tables beginning on page 197 give 

 the analyses, so far as total nitrogen, available phosphoric acid 

 and potash are concerned, for the years 1904, 1905, and 1906. 

 When the gurantees have been changed from that of previous 

 years, the fact is indicated by a foot note. 



In studying the table of comparisons of the analyses of Station 

 samples for three years, it will be found that many goods run 

 quite uniform year after year. This is particularly true as 

 regards phosphoric acid, and this is readily understood when it 

 is remembered that the superphosphate is the starting point and 

 that the materials furnishing nitrogen and potash are usually 

 added to this. The potash and nitrogen are the more expensive 

 substances in fertilizers and the more difficult to mix and hence 

 greater variation is found in these constituents. 



