WATEK — SOILS. 837 



Ne"w researches into Pouillet's phenomenon (the heat developed 

 in wetting powders), T. Martini {Atti. M. Inst. Voicto, 59., jjt. ,J, p. 

 67 J/ ol»<. Ill Plul. Mag. andJour. Sei.,5. ser..,50 (1900), JVo. 307, j)j). 

 618., 619). — Investigations are reported which show that there are cer- 

 tain substances, such as finely g-roimd thermometer-glass, quartz, cal- 

 cium carbonate, etc. , which moisten well with water or other liquids, 

 but which produce little or no heat under such treatment, while other 

 substances, like powdered silica, the silicates, "vegetable earth," and 

 "artificial coal," show decided rise in temperature when moistened with 

 water, alcohol, ether, etc., the rise in temperature being greater the 

 drier the powder. By carefuU}'^ drying the materials the author 

 obtained much higher figures for rise in temperature in silica and 

 animal charcoal than were reported in a previous paper. ^ In the 

 author's opinion the development of heat "is produced by the modifi- 

 cation that the liquid undergoes when absorbed by the powder, by 

 means of which modification the liquid is reduced to a condition of 

 lower molecular energy." The experiments recorded are thus a con- 

 tribution to the new theory of solid solutions. An application of this 

 property of finely ground substances {Benetzungsiodrme) to the exam- 

 ination of soils has been noted (E. S. R., 11, p. 1022). 



Recent observations on the diluvial formation in the Nether- 

 lands with special reference to charting, II, H. Van Cappelle 

 {2Itdr<L Gad. Xcthei'Jands^ Coniniisxie Geol. Onderzo^l:, 1900, iV^>. 27, 

 pj). 25, Jigs. 3, chart 1). — In this, the author's second paper on the 

 suliject, he discusses briefly the position of the moraine covering, of 

 the sand, and of the loess formation in the Veluwe plateau in Gelder- 

 land. The moraine caps are infrequent and are sometimes covered 

 with sand or gravel. Both the sand and gravel are of preglacial ori- 

 gin, and have evidently been washed down from the hills, of which 

 there are many in this region. 



The loess covers the tops of the hills, being thickest in the highest 

 parts, and gradually mixed more with sand in the lower parts. This 

 formation is extremely fertile and is known as the beechland because 

 of the great development of beech trees on this soil. A stratified 

 structure is apparent only when finer or coarser gravel has been mixed 

 with the cla3^ The loess is closely related to the German Rhine-loess, 

 and was laid down by the Rhine and the Yssel long before these 

 streams had cut out their beds to the present level. 



The author concludes that this deposit took place during the time 

 that the second ice sheet approached the borders of the Netherlands 

 and when also the Swiss glaciers spread far beyond their present 

 boundaries. 



There are two appendixes, in the first of which the phj^sical struct- 

 ure of the Netherland loess is compared with other similar formations. 



iPliil. Mag. and Jour. Sci., 5. ser., 1899, No. 286, pp. 329, 330. 



