MISCELLANEOUS. 95 



Oil the cause of the cementing' value of rock pOTvders and the plasticity of 



clays, A. S. Cushman {Jour. Amer. CJiein. Soc, i25 [1908) , No. 5, pp. 4''^1-4'>S, fig.<i.3). — 

 A series of comparative studies are reported which lead to the conckisions " (1) that 

 the cementing power of rock powders is a property similar to the plasticity of clays; 

 (2) that all rock powders that have cementing power show the same peculiar relation 

 to water that is shown by substances that possess an amorphous colloid structure, i. e., 

 they can be dehydrated and rehydrated, until, by jirolonged high heating, the struc- 

 ture is destroyed." Page's method of testing the cementing value of rock powders, 

 which was used in the experiments reported, is in brief as follows: "The stone or 

 other material is ground in a ball mill until it passes a screen with 40 meshes per cen- 

 timeter (100 per inch). This sifted powder is then mixed with sufficient water to 

 make a stiff 'dough.' After standing 24 hours, cylindrical briquettes are made of 

 standard size (25 mm. by 25 mm.) at a standard pressure of 100 kg. per square centi- 

 meter. This is done in a specially designed hydraulic press. The briquettes are 

 then dried in an air bath at 100° and tested in an impact machine which delivers a 

 standard blow of 1 kg., falling 1 cm. The cementing value is measured in this labo- 

 ratory by the average number of standard blows that a series of briquettes made from 

 a rock powder Avill stand." 



Machines at the general agricultural congress at Paris, M. Ringelmanx 

 {Jour. Aqr. Prat., n. ser., 5 {1903), Noa. IS, pp. 404-4^1, .fjg-^- U; U, PP- 437-440, fig^f. 

 8; 15, pp. 470-475, figs. 12). — This includes a general account of the exhibit of agri- 

 cultural machinery at this congress, and describes special forms of machines of the 

 following classes: Machinery and inqilements for (1) preparing the soil, (2) for 

 seeding and sulisequent culture, (3) for harvesting the crop, (4) for preparing the 

 crops for use, and (5) for miscellaneous purposes. 



Fertilizer machinery {Ampr. Ferf., 18 {1903), No. 6, pp. 5-19, tiy.-<. 19). — Various 

 machines used in the preparation of fertilizers on a commercial scale are described. 



Tests of machines for the decortication of rice in Madagascar, M. Ringel- 

 manx {Ayr. Prat. Pays Chauds, ^-' (1903), No. 12, pp. 697-702, fiys. ,?). —Tests of 4 

 machines for this purpose are reported. 



Cold-storage building, J. B. Reynolds ( Ontario Ayr. Col. and E.rpt. Farm Rp>t. 

 1903, pp. 0-9, figs. 6) . — An account is given of the construction of a cold-storage 

 building using mechanical refrigeration, with a summary of results of experiments 

 with it, Avhich have been reported elsewhere. (E. 8. R., 14, p. 866.) 



Cooperative granaries and structures for drying grain, M. RinctELmann 

 {Jour. Ayr. Prat., 3. ser., 5 {1903), No. 19, pp. 600-003).— Prexious articles on this 

 and related su1)jects are noted and a number of structures m actual use are described. 



Notes on stable ventilation, Noack {Devt. Landv. Presse, 30 {1903), No. 34, 

 p. 2S9). — Brief remarks on the importance of adequate ventilation even for piggeries, 

 and on means of securing it. 



Whitewash and lime paints for farm buildings, 31. RiN(iELjiANN {.Tour. Agr. 

 Prat., n. ser., 5 {1903), No. 16, pp. 501, 502). — Various fonuulas are given. 



MISCELLANEOUS. 



Fifteenth Annual Report of Louisiana Stations, 1902 { Looixlaiia, Stas. lipt. 

 1902, pp. 24). — This contains a summary of the work of the Sugar Station at Audu- 

 bon Park, the State Station at Baton Rouge, and the North Louisiana Station at 

 Calhoun, an outline of the work of the State geological survey, a list of publications 

 issued by the stations, organization lists, and a financial statement for the fiscal year 

 ended June 30, 1902. Results in 1901 and 1902 of conq)arative tests of sugar-cane 

 seedlings are brifly rejiorted. 



Eighteenth Annual Report of Maine Station, 1902 (Maine Sta. H})t. 1902, 

 pp. 226). — This is made of reprints of Bulletins 7vt-SS of the station on the following 



