I4S 



NATURE 



[September 30, 1920 



^An expedition which had aeroplanes at command 

 would have the advantage of photojjraphic maps of 

 the whole district it proposed to explore, and could 

 therefore choose the best routes. Supplies also, which 

 would take days to carry by canoes and porters, might 

 be brought from the coast by air in a few hours; and 

 one has only to read the accounts of previous expedi- 

 tions to realise what a difference it would have made 

 in the results had the geography of the country been 

 known in advance and had there been no fear of 

 scarcity of provisions. 



.-Xmong the many ways in which aircraft could 

 help in meteorology, not the least useful would be 

 an examination of the trade winds, especially as 

 regards their variations in altitude and their vertical 

 components in different latitudes. At the present time 

 not much more is known about these winds than their 

 velocities and distribution on the earth's surface. 



Exploration and meteorology are scarcely, or onlv 

 indirectly, commercial matters, and comparatively few- 

 aircraft would be required for the purposes suggested, 

 but results of great value might be obtained bv their 

 use. A. Mali'ock. 



September 21. 



Minerals Hitherto Unknown in Derbyshire. 



During the past three years I have Ijeen conducting 

 investigations relating to the mineralogy of Derby- 

 shire, checking and confirming (or contradicting) 

 asserted occurrences, surveying mineral deposits, and 

 also prospecting, with the result that several minerals 

 — chiefly of scientific interest only — hitherto unknown 

 in Derbyshire have been discovered. The work is not 

 quite completed, and I have not yet issued any paper 

 or other publication upon it, but the following observa- 

 tions may be worth putting on record now : 



Zaratite, Nickel-ore. — Samples of this mineral, of 

 a pale emerald-green colour, and usually containing 

 a large quantity of hydrozincite, were recently found 

 in old dumps of decomposed dolerite raised during the 

 early w-orking of a local mine driven in search of lead- 

 ore. When following up the search for further nickel, 

 some nickeliferous hydrozincite (or zinciferous zara- 

 tite) was found which was of a blue colour instead 

 of the pure green of zaratite. On analysis this was 

 found to contain cobalt, w'hich probably existed as 

 reniingtotiite, the accompanying zinc and nickel exist- 

 ing as their hydrous carbonates. The " mineral " is, 

 therefore, probably a mixture of the three mineral 

 species, hydrozincite, zaratite, and remingtonite. 



Considerable difficulty attaches to the following up 

 of such finds with the view of ascertaining the quantity 

 available, as manv of these mines are of considerable 

 antiquity and dilapidation, having been driven in 

 search of lead-ore when little or nothing was known 

 of the rarer metals. 



Nephrite, Jade. — Near the margin of a basalt quarrv 

 at Bonsall a somewhat lenticular nodule-shaped lump 

 of white nephrite was found. 



Diabantite. — Beautiful specimens of this uncommon 

 member of the chlorite group of complex silicates 

 were found at Mill Close Mirje, Darley Dale, having 

 been raised during the early workint? of the mine. It 

 occurs in the much decomposed dolerite as radiated 

 spherical aggregates (up to 2 cm. diameter) and of a 

 dark green colour. It is usually associated with 

 calcite in amygdaloidal cavities, has a specific gravitv 

 of 279, a hardness of 2-3, and is strongly pleochroic. 



CinwUie. — .\. hydrous aluminium silicate. .\ tFiin 

 bed of this mineral occurs near Hopton. It is quite 

 white, amorphous, and chalk-like. 



Allophane. — A, hydrous aluminium silicate. Many 

 of the numerous rake-veins in the mountain limestone 



NO. 2657, VOL. 106] 



of the Middle Peak region are rich in forms of 

 limonite, but chiefly the earthy variety. — ochre. In one 

 of tfiese veins which is cut in the Coal Hills Quarry, 

 near VVirksworth, allophane is to be found in more 

 than one form. The commonest form is that of a 

 light amorphous powder ; it also occurs as an opaque, 

 white encrustation, and as a translucent, sub- 

 crystalline encrustation of the faintest green tinge due 

 to the presence of a minute trace of malachite. 



Utalvte (?). — The limestone-shale in the vicinity of 

 Wensley contains a quantity of an insoluble basic 

 ferric sulphate as dull, yellowish-brown films in the 

 shale. Its mode of occurrence renders its accurate 

 analysis difficult, but it seems to be a variety of 

 utahite. 



Native Sulphur. — " Native sulphur is said to have 

 been found " is recorded by ancient writers, but no 

 confirmation in recent years seems to have been made. 

 .\ good specimen was recently found near Eyam. It is 

 a greyish-yellow powder, burning readily when ignited. 



Manganese-ore. — Manganese is not a new discovery ; 

 the indefinite hydrous oxide — wad — has long been 

 known to exist in certain districts in the county. It 

 has also been previously worked, but the present 

 scarcity (recently mentioned in the House of Com- 

 mons) led to the work of prospecting for a deposit to 

 be mined on as large a scale as possible. This work 

 has been successful, and arrangements are being 

 made, by the company for which the work was under- 

 taken, for the mining of the ore. 



C. S. G.\R\f.TT. 



Riber View, Oak Road, Matlock, 

 September 16. 



i 



Wheat-bulb Disease. 



In view of their economic bearing and of the near- 

 ness of the wheat-sowing season, the data given below 

 .should be widely known, all the more that in the 

 latest notice I have seen regarding the life-historv of 

 the insect pest concerned (Kev. Applied Ent'om., 

 June, 1920, abstract of papers by R. Kleine in 

 Zeitschr. f. angeiv. Ento7n., Berlin, 1915-16) the 

 practical conclusions given appear to be entirely mis- 

 leading. These conclusions are that '" wheat should 

 be preceded by root crops " and "it is apparently use- 

 less to attempt to grow wheat or rye on ground which 

 has not been under cultivation for some time." Now 

 it is chiefly among root crops, especially potatoes, and 

 on fallow ground that the insect elects to lav its 

 eggs. This month, for example, in one infected area 

 I find that the number of potential " wheat-bulb " 

 larvae in a particular potato-field ranges from six to 

 twenty per square foot of surface, while the next 

 field (pasture) has very few, and the neighbouring 

 wheat-field, which was the sufferer last spring, has 

 still fewer. Obviously to sow wheat on infected 

 ground means laying up progressive trouble for the 

 future. The disease has done much damage this 

 year in the East of Scotland and elsewhere, and is 

 evidently spreading, in this locality at any rate. 

 Larvae obtained from infected wheat were allowed to 

 pupate in the laboratory here, and the flies which 

 hatched out (Hylemyia coarctata, vide Theobald's 

 ".Agricultural Zoology," 1913, p. 242) were kept until 

 they laid their eijgs. (Two of them still survive, 

 though the field Hylemyias are all apparently dead.) 

 The distribution of the eggs' in nature was then 

 studied (so far as time allowed) by a method 

 permitting accurate enumeration. 



■ J.^MEs F. Gemmii.i,. 



Natural History Department, University 

 College, Dundee, September 23. 



