470 



NATURE 



[August 3, 19 16 



has added to the value of his work by including an 

 exhaustive bibliography of the geology of New 

 Guinea. 



The water-f>ower resources cf the United States 

 continue to be studied in detail by the Geological 

 Survey, and several further reports have been pub- 

 lished. Water-supply Paper 372 deals with a water- 

 power reconnaissance in South-central Alaska, and 

 shows that there is less water-power available in that 

 region than had been supposed, and most of it is 

 unavailable during the winter months. This latter 

 objection could, of course, be overcome by adequate 

 storage reservoirs, which are no doubt possible ; but 

 more accurate surveys are needed before this could be 

 decided. The possible competition of water-power 

 with coal power — for coal occurs in this region — raises 

 important geographical questions, but is outside the 

 scope of the inquiry. A second volume (No. 373) deals 

 with the water resources of Hawaii, but, unfor- 

 tunately, contains no discussion of results. 



The Geological Survey Report, No. 6 of the Depart- 

 ment of Mines, Tasmania, " Reconnaissance of the 

 North Heemskirk Tinfield," by L. L. Waterhouse 

 (1915, pp. iv + 74, 7 plates), describes the economic 

 geology of the mining field, which is situated on a 

 somewhat inaccessible part of the western coast of 

 Tasmania. The oldest rocks are a series of slates, 

 quartzites, and tuffs, which are regarded by Twelve- 

 trees as Cambro-Ordovician, though there is no direct 

 fossil evidence of their age. These rocks have been 

 invaded by Devonian granites and gabbros, and by 

 diabase which is assigned to the same age as the 

 upper Mesozoic sill that is such a conspicuous feature 

 in the central plateau of Tasmania. The only 

 Cainozoic rocks consist of flows of basalt and beds 

 of sandstone and conglomerate, some of which have 

 been cemented into a hard quartzite, such as is often 

 found associated with the Australian basalts. 

 Associated with these rocks are ancient river deposits 

 with tin-bearing gravels. Mr. Waterhouse shows 

 that these are younger than the diabase and gabbro 

 and older than the basalt; hence his geological study 

 of the field helps the prospector by showing that it is 

 no use boring through the older basic rocks in the 

 hope of discovering under them a continuation of the 

 tin-bearing gravels. The tin is primarily due to the 

 Devonian granites, and quartz-tourmaline-cassiterite 

 veins occur around it near Mount Heemskirk. Some 

 primary ores of copper have been found, but also in 

 too small quantities to be of economic value. Some 

 extensive masses of magnetic iron ores occur beside 

 the granite massif, but, owing to their inaccessible 

 position, their tonnage is too small for present use. 

 The value of the field depends upon its alluvial tin 

 ores, which are worked by hydraulic sluicing. The 

 report is illustrated by a useful geological sketch- 

 map. 



The Memoir of the Geological Survey on the country 

 around Milford (1916, price 2s. 6d.) is a further addi- 

 tion to the description of the South Wales coalfield, 

 and includes a petrological account of the Ordovician 

 volcanic rocks of Skomer Id. Dr. Thomas proposes 

 two new names, Skomerite and Marloesite, for types 

 of lava in which albite-oiigoclase is associated with 

 augite in a fine-grained ground. The marloesites 

 contain glomeroporphyritic groups of olivine and alblte. 

 The map given indicates a remarkable variety of 

 igneous typ>es running in parallel bands across the 

 island, and summarises the work already published by 

 Dr. Thomas in igii. 



Mr. S. Taber publishes in the American Journal of 

 Science, vol. xli. (June, 1916), p. 532, a paper, based 



NO. 2440, VOL. 97] 



on experiments, on "The Growth of Crystals under 

 External Pressure," which has a wide geological 

 bearing. Previous workers have held contradictory 

 views as to the reality of a crystallising force, which 

 the author reconciles by showing that " a crystal 

 surface will not grow under pressure and therefore 

 will not do work in overcoming external forces resist- 

 ing growth unless the surface is in contact with a 

 supersaturated solution." He suggests that the out- 

 ward pressure exerted by a growing concretion may 

 cause the solution of material, which it gradually 

 replaces. On the other hand, when a material has its 

 solubility increased by pressure, there is a contraction 

 of the total volume, and the separation of such a sub- 

 stance again from solution in a closed and limited 

 space, as in the capillary passages of a shale, may 

 develop enormous pressure. Is the author right, how- 

 ever, in stating that concretions in which the bedding 

 planes are retained, and not thrust aside, are rare in 

 shales ? 



The report of the Chief Inspector of Mines in My- 

 sore for the year 19 14 has just been issued, and shows 

 quite a flourishing state of affairs. The staple mining 

 industry is, of course, gold mining, and the pro- 

 duction for the year amounts to 562,617-56 ounces, 

 being an increase of about o'2 per cent, on the previous 

 year. It is a very satisfactory feature of the report 

 that this production was obtained with a considerably 

 greater measure of safety so far as the workers are 

 concerned ; the death-rate in the gold mines was 228 

 per thousand, as against 438 in 1913, whilst the 

 number of serious injuries also shows a marked 

 decrease. A considerable proportion (27*9 per cent.) 

 of the fatalities were due to the air-blasts that form 

 such a marked characteristic of the Kolar gold 

 mines. Much attention is being given to these air- 

 blasts, which are due to the splitting off of masses 

 of the country rock, which appears to be in a condition 

 of excessive internal strain, and the methods recently 

 adopted of closely stowing the stoped-out areas with 

 waste rock appears to have been attended with de- 

 cidedly beneficial results. Of the other mineral pro- 

 ducts, manganese ore is the most important, the 

 output being given as 18,055 tons, as against 10,501 

 tons in 1913. Small quantities of chromite, magnesite, 

 mica, asbestos, and corundum have also been pro- 

 duced, but none of these minerals are as yet being 

 got in any important quantity. 



The Meteorological Service of Canada has intro- 

 duced a change in its monthly record of observations, 

 and the issue for January, 1916, which has recently 

 been received, gives data in more extended detail than 

 formerly. Under the directorship of Mr. R. F. j 

 Stupart the results published are of a high scientific i 

 value, and deal practically with every branch of j 

 meteorology. A detailed list is given of the stations j 

 used, which shows a very extensive and complete | 

 series of observations. Hourly observations of pres- i 

 sure, temperature, and humidity are given at selected | 

 stations, and there are detailed observations of rain-1 

 fall, sunshine, and wind. The weather conditions! 

 during January, 1916, were far from normal, and it} 

 is mentioned that the result of the persistent far 

 southerlv course of the depressions tracked from th 

 Pacific Ocean was a continuance of northerly wind 

 and almost unprecedented cold in British Columbia 

 and the Western Provinces. A map for the area under 

 discussion, exhibiting the difference from average 

 temperature, shows a deficiency of 20° F. over Yukon, 

 and as much as 25° F. in British Columbia, whilst the; 

 eastern half of the Dominion experienced very mildi 

 weather with much rain. It will be remembered thatj 

 over England, and generally on this side of thes 



