September 9, 1909] 



NA TURE 



Co 



varied geological history than this, and the rapidly in- 

 creasing literature dealing with it has scarcely reached 

 a stage in which a short summary of results is possible. 

 Dr. Cvijic's paper is accompanied by maps and sections 

 and a number of excellent characteristic photographs. 



We have received the annual report of the Survey 

 Department of British East .Africa for the financial year 

 iqo7-8, by Major G. E. Smith, R.E., director of surveys. 

 The report is divided into three sections, trigonometrical 

 ■branch, cadastral branch, and Uasingishu Rapid Allot- 

 ment, and each branch shows very good progress. The 

 trigonometrical branch having completed the preliminary 

 astronomical observations and base measurements on the 

 Athi plains near Nairobi last year, has been able to make 

 rapid progress with triangulation, 7320 square miles having 

 ■been completed in 1907-8, as against 1375 in 1906-7. In 

 the cadastral branch the arrears of farm surveys have been 

 reduced to manageable proportions, and systematic mapping 

 should get oiT rapidly next season. 



The director-general of Indian observatories reports that 

 the monsoon appeared about a week before its normal date 

 •over the Bay of Bengal, and advanced inland with the 

 usual rapidity ; the Bombay current also arrived about the 

 normal date, but did not penetrate inland in full strength 

 until nearly the end of June. The aggregate rainfall of 

 June and July in the plains of India was 13 per cent, in 

 excess of the normal, excepting in the provinces of Central 

 India, the Central Provinces, and Mysore, where there 

 was a deficit, especially - in the latter State. Abundant 

 monsoon rainfall is, as a rule, preceded by high pressure 

 in South America and low pressure in the Indian Ocean. 

 These favourable conditions were fully maintained during 

 June and July, and the director-general infers from this 

 fact and other data that the total amount of rainfall in 

 August and September will exceed the average. 



Much useful information relating to aerial navigation 

 and the physics of the upper air is contained in the re- 

 ports of scientific lectures and papers published in the 

 weekly review of the Frankfort Aeronautical Exhibition. 

 The number for August 14, for instance, includes (i) an 

 illustrated account of the use of pilot balloons by Mr. H. 

 Bongards, which show the direction and velocity of the 

 upper wind currents. Dr. de Quervain first constructed 

 a. special theodolite by which the motion of the balloons 

 could be easily followed in clear weather up to an altitude 

 of 15,000 metres. At Frankfort an apparatus by Dr. 

 Assmann is used for the purpose. (2) A preliminary report 

 of a lecture, by Dr. Putter, on the development of flight 

 in the animal kingdom, in which the different muscular 

 motions are explained. The author stated that about 

 62 per cent, of some 420,000 objects, including insects, 

 birds, bats, and fishes, were endowed with some means of 

 flight, and his views of the future development of our 

 present flying apparatus were very promising. 



The so-called Roman amphitheatre at Charterhouse-on- 

 Mendip, about seven miles north-west of 'VVells, has recently 

 been excavated by Mr. H. St. George Gray on behalf of 

 the Somersetshire Archaeological Society. It was certainly 

 closely connected with the extensive Roman lead-mining 

 operations in the Mendips, which, with the remains dis- 

 covered from time to time, have been fully described by 

 Prof. Haverfield in the "■Victoria County History." So 

 far as the discovery of relics goes, the present operations 

 were disappointing. Flint implements are numerous, and 

 when discovered associated with Roman remains it is 

 NO. 2080, VOL. 81] 



safe to infer that the lead-miners found them on the 

 surface and buried them in their excavations. The arena, 

 according to Mr. Gray, may have been used by the Roman 

 miners for games, combats, or cock-fighting, but it is 

 ridiculous to style it an amphitheatre of the class of the 

 Maumbury Rings at Dorchester. In fact, the use of such 

 a term raises, as Prof. Haverfield says, " false ideas of 

 space and grandeur"; and he goes on to say that "we 

 cannot decide its precise use, but it is ill-suited to form 

 a pond or water reservoir, and the notion of a tiny 

 amphitheatre is not wholly absurd." 



C0NSIDER.4BLE progress towards the settlement of the 

 ever-recurring controversy regarding the origin and date 

 of the so-called dene-holes has been made in a paper con- 

 tributed to the January-June number of the Journal of the 

 Royal Anthropological Institute by the Rev. J. W. Hayes. 

 This contribution is somewhat lacking in lucidity and 

 logical arrangement, but the writer has pursued the in- 

 vestigation in a common-sense way, and has collected a 

 mass of facts necessary to the settlement of the problem. 

 It is essential to know the various qualities of chalk, and 

 the uses to which it was put in ancient and modern times. 

 The export of the material began in pre-Roman time, and 

 the character of it varied. It was essential for the 

 purposes of home and foreign trade that it should be 

 excavated in solid blocks, and the occui'rence of strata 

 of this quality accounts for the grouping of a number 

 of pits in the same neighbourhood. It was and is raised 

 in buckets or baskets, and difliculties of carriage suggested 

 the construction of fresh shafts in close proximity to each 

 other. These considerations seem to dispose of the objec- 

 tion that excavation for the material was only one of the 

 objects of the construction of the dene-holes as we find 

 them. One of the strongest reasons against the theory 

 that they were used as granaries or hiding places lies in 

 the fact that they contain cores of sand, which could not 

 have arisen from attrition of the sides of the pits or from 

 collapse of the mouths of the excavations. These cones 

 could only have resulted from the deposit in the worked- 

 out pits of debris from those of later construction. Mr. 

 Hayes has collected a mass of reports from persons 

 engaged in the chalk trade in recent times which show 

 the methods by which the material is excavated and 

 utilised. These raise a strong presumption that the same 

 considerations which now influence the workers prevailed 

 also in the British and Rom.an periods. 



In the Electrician for August 20 Mr. Morris-Airey makes 

 a suggestion which may prove the correct explanation of 

 the discordant results obtained when two lights of different 

 colours are compared together by photometers of the 

 Bunsen and of the flicker type respectively. The three 

 groups of nerve fibres in the retina, which respond re- 

 spectively to red, green, and violet light, behave, according 

 to Mr. Morris-Airey, in different ways when the stimulus 

 is first applied, the red group, e.g., responding more 

 quickly than the violet, so that the true degree of excita- 

 tion of the nerves corresponding to a stimulus is attained 

 by the red nerves before it is by the violet. If the speed 

 of the flicker photometer is such that the stimulus is not 

 applied long enough to allow the three sets of nerves to 

 attain the proper degrees of excitation, the results of com- 

 parisons of lights of different colours will vary with the 

 speed, and will only agree with the Bunsen results when 

 the speed is reduced sufficiently. 



According to the July Bulletin de la Sociiti d'Encourage- 

 meni pour I'Industrie nationale of France, the society is 



