June 5, 1919] 



NATURE 



265 



I venture to say that an equally favourable oppor- 

 tunity for initiating the reform will not occur until the 

 same almanac is repeated in 1936, when, however, it 

 is complicated by a leap-day. Alexr. Philip. 



The Mary Acre, Brechin, N.B., May 8. 



Glossina and the Extinction of Tertiary Mammals. 



Dr. G. D. H. Carpenter (Nature, March 20, p. 46) 

 asks why we should suppose that the occurrence of 

 tsetse-flies (Glossina) in the Miocene of Colorado 

 might have had anything to do with the extinction 

 of some of the large Mammalia. He points out that 

 such flies exist in Africa to-day, carrying trypano- 

 somes, and the native Mammalia nevertheless survive 

 and flourish. It is known, however, that in Miocene 

 times there were extensive migrations of animals, 

 from mammals to insects, and the New and Old 

 Worlds each received important contributions from 

 the other. In such periods of migration it is p>er- 

 fectly conceivable that Glossina might appear in a 

 new region, carrying a trypanosome which would be 

 highly pathogenic for certain elements of the resident 

 fauna. Even in Africa we do not know what animals 

 may be absent to-day owing to the former prevalence 

 of disease-producing organisms. 



T. D. A. COCKEREIX. 



University of Colorado, Boulder, Colorado, 

 April 24. 



INDICATIONS OF OIL IN DERBYSHIRE. 



AFTER a somewhat lengthy interval, the atten- 

 tion of the public has again been directed 

 to the Government drilling operations for oil in 

 this country. On May 26 the Times described the 

 progress which had been made in the work, and 

 stated that several of the bores had now reached 

 a critical depth. At any moment oil might be 

 discovered. This was followed three days later 

 by the announcement that oil had been found in 

 the Hardstoft No. i boring near Chesterfield. 

 Further details added that the oil had risen 

 1000 ft. in the well. The form of the announce- 

 ments was somewhat misleading, and they need 

 to be stripped of their trappings to arrive at a 

 true perspective. A show of oil has been found 

 at Hardstoft — nothing more. Such shows of oil 

 have been found before in the British strata, and 

 have invariably proved to be of little or no value. 

 It remains to be proved that the present indica- 

 tions at Hardstoft are of a different calibre, and 

 it would have been well to postpone, or at least 

 moderate, the announcement of the discovery 

 until the resumed drilling operations had indi- 

 cated the quantity of oil which was forthcoming. 



The position of the general drilling operations 

 in Britain may be summarised as follows. Wells 

 are being drilled in three areas, Chesterfield, 

 North Staffordshire, and Midlothian. The opera- 

 tions in the last two areas are merely in their pre- 

 liminary stages, but in the Chesterfield region the 

 work is further advanced, and two of the seven 

 I wells — namely, Brimington and Hardstoft No. i 

 — have almost attained their proposed depths. 

 Shows of gas have been encountered in several 

 of the bores, but the porous horizons of the Mill- 

 stone Grits, where pierced, have in all cases failed 

 to produce the oil which was anticipated. To this 

 NO. 2588, VOL. 103] 



extent, then, the results have been disappointing. 

 However, it has never been intended to limit 

 exploitation to the Millstone Grits. The under- 

 lying Carboniferous Limestone has been con- 

 sidered by some to be a better horizon for testing, 

 and the wells are being continued through the 

 Yoredale Shales in order to pierce this formation. 

 Both the Hardstoft No. i and Brimington bores 

 have almost reached the Carboniferous Lime- 

 stone, and the oil which is announced in the 

 former probably comes from the beds near the 

 junction. 



It must be emphasised that there is nothing in 

 the present situation to warrant the unduly opti- 

 mistic attitude of a section of the Press. The 

 statement that this is the first discovery of oil in 

 substantial quantity in England is incorrect, and 

 greatly exaggerates the present indications. The 

 announcement that the oil has risen 1000 ft. in 

 the well may bear two interpretations. It may 

 be that the whole liquid column is composed of 

 oil, or it may be merely an upper layer of oil 

 floating on a column of water, as in the case of 

 the Kelham bore. The shales and banded lime- 

 stones immediately above the main limestone in 

 Derbyshire often contain small quantities of 

 petroleum, though the porosity of these strata is 

 too small to yield large quantities of the material. 

 It is possible that every well which is sunk into 

 these beds will yield some indications of petrol- 

 eum, but the small porosity and other factors of 

 preservation limit the hope of a commercial pro- 

 duction of petroleum. 



Judgment must be suspended until the results 

 of the resumed drilling operations are known. In 

 the meantime it is fortunate that the Government 

 has prevented promiscuous drilling, and thus 

 minimised the evils of fevered financial specula- 

 tion. The Canadian oil boom of 1914, based on 

 an oil show similar in type to the present indica- 

 tions at Hardstoft, and which ended in nothing, 

 is a typical example of these deplorable scrambles. 



V. C. Illing. 



THE SOLAR ECLIPSE. 



TELEGRAMS received by the Astronomer 

 Royal report that at the station at Sobral, 

 in Brazil, occupied by Dr. Crommelin and Mr. 

 Davidson for photographing the field of stars 

 round the sun on the occasion of the total eclipse 

 of the sun last week (May 29), the sky was clear 

 for at least part of totality, and that the pro- 

 gramme was satisfactorily carried out. The photo- 

 graphs have been developed, and all the stars 

 expected are shown on the plates taken with the 

 astrographic lens, as well as on those taken with 

 a second telescope lent by Father Cortie. The 

 expedition will remain at Sobral until the neces- 

 sary comparison photographs are taken in situ. 

 The message from Prof. Eddington at Prince's 

 Island, off the coast of West Africa, which reads 

 "Through cloud, hopeful," may be taken to imply 

 that some success will also be derived from the 

 work of this expedition. 



