746 EXPEKIMENT STATION EECORD, 



relating to Australia are noted and its general flimatic conditions, especially as 

 regards rainfall, are discussed. The geological and physical characteristics of the 

 great central artesian basin of Australia are- discussed in detail. Among the con- 

 clusions reached are: 



"That a comparatively small percentage of the rainfall over the interior of the 

 continent is absorbed by the exposed marginal outcrops and carried to the retaining 

 gravel beds that underlie the clays, and when these overlying impervious strata are 

 pierced by the borer's drill, at lower levels than the source of supply, the impounded 

 waters beneath the clayey strata flow to the surface. 



"That from the elevated intake beds there is a very slow circulation of the under- 

 ground waters toward the lower levels of the central portion of the continent, where 

 there is leakage in the form of natural artesian sjirings and marshes— such being 

 favored by the local conditions to which I have alluded. 



"That, besides these natural springs at the bottom of the great central trough, 

 there are others where weak portions of the strata occur within the region. 



"That the great storage beds are periodically replenished l)y the quantity of water 

 alisorbed at the outcrops. 



"That the absorbing process is temporarily suspended when the water-carrying 

 be<ls have been tilled. 



"That there is upward as well as downward percolation of artesian water. 



"That by far the greater portion of the rainfall over the inland regions of Australia 

 and the leakage waters from the storage beds are evaporated. 



"That there is no available evidence of submarine leakage of the artesian waters 

 of Australia. 



"That, on the contrary, the balance of evidence and of reasons is directly opposed 

 to the theoi-y of such leakage." 



Chemical-geolog-ical investig-ations on the absorptive properties of decom- 

 posed rocks, M. DiTTRicn {Mitt. Grossherz. Bad. Geol. Landes-Aufnahme, 4, No. 3; 

 ahs. in Centhl. Agr. Chein., 31 {1902), No. 12, pp. 793-796). — In these investigations 

 25 gm. of weathered rock (hornblende granite) was treated at room temperatures for 

 2 days with normal, yV-^^ormal, and yjjj-normal solutions of sodium, potassium, 

 ammonium, calcium, and magnesium chlorids; and potassium nitrate, sulphate, and 

 carbonate, the composition of the extract thus obtained being determined. With 

 tenth-normal sodium chlorid solution considerable amounts of lime and magnesia 

 were dissolved, while an equivalent amount of soda was retained by the rock, and 

 only traces of potash were found in the extract. These changes took place very 

 soon after the solution was added-, and with 8 days' digestion the results were the 

 same as with 2. With the hundredth-normal solution the amount of lime dissolved 

 was increased, while with normal solution it was decreased. With potassium chlorid 

 solutions the reactions were much the same in kind as with sodium chlorid solutions 

 and proceeded more rapidly. Despite the fact that the rock was already rich in 

 potash, it absorbed considerable amounts of jiotash from the solution. The amounts 

 of lime and magnesia dissolved were double those removed by the sodium chlorid 

 solution. The behavior of ammonium chlorid solution was similar to that of potas- 

 sium chlorid. In both cases there was apparently a chemical union of the base with 

 the constituents of the rock. Little change was observed in case of the solutions of 

 calcium and magnesium chlorids. Potassium nitriate and sulphate behaved like the 

 chlorid, indicating that with neutral salts the reactions depend upon the base and 

 not upon the acid. With calcium carbonate, an alkaline salt, almost no lime and 

 magnesia were dissolved, but more than a third of the potash, with a corresponding 

 amount of carhon dioxid, were al)sorbed I-y the rock. 



Geology and water resources of the Snake River Plains of Idaho, I. C. 

 Russell {U. S. Geol. Survey Bui. 199, pp. 192, ph. 2rj,fi,gs. 6).— This report is based 

 on the results of field work carried on from July 5 to September 12, 1901, the main 



