759 



In all these processes the calcium sulphate may hinder the reactions 

 by preventing the most advantageous conditions lor the action of free 

 phosphoric acifl. 



The above indicates that the tricalcic phosphate by its action on the 

 monophosphate causes very interesting and significant changes. 

 . Report of the agricultural chemical experiment station at Halle for 1890, 

 M. Maercker {Zeitsch. d. landw. Central- Vereins d. Frov. Sachsen, 1891, 

 pp. 105-114). — This station, which is the station of the Central Agiicul- 

 tural Society of the Province of Saxony (Prussia), is located at the 

 Agricultural Institute of the University of Halle. The director, Dr. 

 Maercker, is also professor in the university. It has a branch station 

 {Filiale) located at Magdeburg, under the direction of Dr. Waas. 



The report for 1890 shows the personnel of the central station to con- 

 sist of a director, assistant director, botanist, eight assistants, a secre- 

 tary-i an accountant, a gardener, and three helpers ; and that of the 

 branch station at Madgeburg to consist of a director, an assistant, and 

 a helper, making 21 members of the working staff. 



The work of the year included analyses, field and feeding experiments, 

 experiments in sugar-beet culture, studies of soils, botanical examina- 

 tions, tests of varieties, seed control, and distillery experiments. The 

 analytical work of the main station was as follows : fertilizers, soils, etc., 

 3,223; feeding stuffs and sugar-beets, 1,814; botanical examinations 

 (seed tests, etc.), 1,166: soils, with reference lo phosphoric acid, 303; 

 making in all 6,506 analyses. The branch station examined 1,901 sam- 

 ples of feeding stuffs and milk, and 397 samples of fertilizing materials. 



In his review of the general quality of fertilizers and the extent of 

 their use the past year, the author remarks upon the increased use of 

 Thomas slag on fields used for sugar-beet culture, as well as on lighter 

 soils and meadows, and states that 14 cases of adulteration of this 

 ground slag with Uedonda phosphate were noticed during the year. 



In the botanical laboratory 547 samples of seeds and 298 samples of 

 feeding stuffs were examined as to their purity. The author commends 

 the work in these directions very highly, and regards a botanical 

 laboratory, under the direction of a competent head, as of the utmost 

 importance to every experiment station. 



The majority of the experiments carried out by the station receive 

 but brief mention in the short report given, the details and conclusions 

 being reserved for future publication. The studiesof soils withreference 

 to phosphoric acid content are, however, reported at considerable length. 



To study the relation of the phosphoric acid contained in different 

 soils to plants growing in them, vegetation experiments were made with 

 samples of typical soils containing in some cases like percentages and 

 in others different percentages of phosphoric acid. The same kind of 

 plants were grown in all cases, and at the end of the season determina- 

 tions were made of the amount of phosphoric acid given up to the plants 



