142 



The referee desires to remind the analysts cooperating in this work that it has been 

 undertaken under the auspices of the A. O. A. C. for the purpose of establishing, if 

 possible, a standard method for the estimation of iron and alumina which should have 

 the indorsement of the association. At present all is chaos, and when two chemists 

 differ on iron and alumina it is impossible to say who is right and who is wrong. 



The great majority of rock sales to-day are settled either by Gladding method or by 

 the G laser method, as outlined above. 



The referee submits the above modification of the acetate method, which he believes 

 to be simpler and fully as accurate as the others, and will welcome the comments 

 and criticisms of the analysts when they have completed the work on the three samples 

 by the methods outlined above. In regard to the synthetic solution sent, the referee 

 would say that it was not practicable to send more than 300 cc to each analyst, but 

 that in his opinion one-half gram, or 50 cc, is sufficient for any of the tests required, 

 and used in this way there is sufficient of the synthetic solution for six tests. 



Reports were received from six chemists cooperating in the work on iron and alu- 

 mina, whose results are given in the following tables: 



Determination of iron and alumina in Tennessee and Florida rock. 

 TENNESSEE ROCK. 



o Omitted from average. 



* Per cent calculated from average of three determinations. 



