NATURE 



[May 6, 1909 



(i) if the effect of temperature on the ionisation produced 

 in tfiese gases and vapours were the same as for air ; 

 (ii) if cooliiig down air to a temperature near its condensa- 

 tion point produced any appreciable alteration in the 

 ionisation produced in it by rays of given intensity. As 

 it is almost impossible So clean out completely a vessel 

 which has once contained organic vapours, the second 

 c xpcriment was performed first. The ionisation produced 

 by Rontgen rays has been measured in air at the tempera- 

 ture of liquid air, and in ethyl bromide and methyl iodide, 

 at various temperatures up to 184° C. It was found that 

 in every case the amount of ionisation produced was in- 

 dependent of the temperature of the gas if the density of 

 the gas remained constant. — The wave-making resistance 

 of ships : a theoretical and practical analysis : T. H. 

 Havelock. The usual estimates of the wave-making 

 resistance of ships rest on a formula obtained for " two- 

 dimensional " motion, that is, for motion confined to trans- 

 verse waves of uniform height ; if a is the amplitude of 

 the waves and -j their velocity, the wave-making resist- 

 ance R is proportional to a" for deep water. Hence there 

 arise formula; which make R proportional to ■«', by sup- 

 posing that a varies as -■-. Regarding, however, the ship 

 as in this respect equivalent to a travelling band of pressure 

 disturbance, a simple type of distribution leads to wave- 

 ridges giving a formula for R in which the velocity enters 

 in the form e-o/i-. This function is shown to have the 

 general character of experimental curves of residuary 

 resistance. From a consideration of the waves diverging 

 from bow and stern, and the interference of these systems, 

 a semi-empirical formula, 



R = a^ - 2"53/9f'' + ;3{ I _ .y cos ( lo-2,V-)| <■ - ='53/f", 

 is obtained. Here R is in lbs. per ton displacement of 

 the ship, and c is the speed-length ratio, viz. (speed in 

 knots)/ ^/(length of ship in feet); a, ^, 7 are adjustable 

 constants, which depend upon the form of the ship. 

 Various e.Kperimental model curves are examined, and it 

 is shown that these can be represented very well by a 

 formula of the above type. It is found that the constant 

 a is small relatively ; and if the comparison is limited to 

 values of c from about oq upwards, the curves can also 

 be fitted by an alternative formula of the type 



R = 6{i - 7 cos ( 10 -a/c^)! £--«/<:=. 

 The effect of finite depth of water is considered, and a 

 modification of the formula is obtained to express this 

 effect as far as possible. .Starting from an experimental 

 curve for deep water, curves are drawn from the formula 

 for the transverse wave-resistance of the same model with 

 different depths ; although certain simplifications have to 

 be made, the curves show the character of the effect, and 

 allow an estimate of the stage at which it becomes appreci- 

 able. Finally, the question of other types of pressure 

 distribution is discussed, and one is given in illustration 

 of the wave-making resistance of an entirely submerged 

 vessel. — The ionisation of various gases bv secondary 

 7 rays : R. D. Kleeman. The ionisations of a number 

 of gases relative to the ionisation of air by the secondary 

 7 rays frorn substances exposed to the 7 rays of radium 

 were measured. Secondary radiators of lead, zinc, and 

 carbon were used. It was found that the ionisations of 

 gases the molecules of which consist of atoms of H, C, 

 N, O, S, CI, with the exception of H,, are practically the 

 same as those obtained with the primarv 7 ravs ; but the 

 secondary rays produce a greater relative amount of 

 ionisation than the primary in gases the molecules of 

 which contain atoms of higher atomic weight than that 

 of chlorine. The ionisation of H, is abnormal ; it is smaller 

 with the secondary rays than' with the primary. The 

 ionisations of the various gases, with the exception of 

 _H,,^ obey approximately an additive law. The atomic 

 ionisations, by means of which the ionisations in the gases 

 can be calculated, increase more rapidly with the atomic 

 weight with the secondary rays than with the primary. 



Geological Society, April 7.— Prof. W. T. So'las, F.R.S., 

 president, and afterwards Mr. H. W. Monrkton, vice- 

 president, in the chair.— Overthrusts at Tintagel (north 

 Cornwall) ; H. Dewey. In this paper the author deals 

 w.th the geological structure of the Tintagel area. After 

 brief reference to the stratigraphy north of Bodmin Moor, 



NO. 2062, VOL. 80] 



mention is made of the apparent difference in order of 

 superposition of the beds near Tintagel. The several 

 types into which the Upper Devonian rocks are divided 

 are next described. — The Lahat " pipe " : a description of 

 a tin-ore deposit in Perak (Federated Malay States) : 

 J. B. Scrivenor. Large quantities of tin ore have been 

 obtained during recent years in the Kinta district of 

 Perak, principally from detrital deposits, but also in some 

 cases from the limestone which forms the floor of the 

 Kinta Valley. From 1903 until 1907 the Soci^t^ des 

 Etains de Kinta secured more than 1000 tons of dressed 

 tin ore from a peculiar deposit which had the form of a 

 pipe in the limestone, measuring only 7 feet by 2 feet 

 at the surface, but widening when followed downwards. 

 It was worked to a depth of 314 feet. The veinstone was 

 a deep red mixture of calcite and iron oxide with some 

 quartz, chalybite, and chalcopyrite, but no tourmaline was 

 found in it. In this the cassiterite occurred in irregular 

 pieces and broken fragments, some of which consisted of 

 radiating needles. In Kinta the tin ores occur in the 

 limestone in two different ways : — (i) As lodes or veins with 

 fresh sulphides, but not iron oxides. The tin-oxide crystals 

 have a definite arrangement. (2) As transformed masses, 

 deposited in fissures. The cassiterite is in rounded grains, 

 and quartz, tourmaline, and other materials, also well 

 rounded, accompany it. The Lahat pipe is a lode deposit 

 which has been converted into a detrital deposit in situ. 

 — The sculptures of the Chalk Downs in Kent, Surrey, 

 and .Sussex : G. Clinch. The author classifies the various 

 forms of sculpture of the Chalk Downs under three heads, 

 namely, (i) dry valleys of simple form ; (2) dry valleys of 

 complex form ; and (3) wet valleys. He directs attention 

 to the relatively small catchment-areas of the dry valleys, 

 and to the large number of tributary valleys found in 

 some districts, two points which he considers have not 

 received hitherto entirely satisfactory explanation. While 

 accepting the view that frozen conditions in former times 

 altered the drainage system of the Chalk, he argues that 

 the most potent excavating force was the frost itself act- 

 ing on Chalk saturated or highly charged with water. 

 He propounds a theory to account for (i) the great size 

 and breadth of the valleys in relation to their catchment- 

 basins ; (2) the ramifications of some of the valley systems ; 

 and (3) the remarkable fact that many dry valleys die out 

 just before the crest of the Chalk Downs is reached. 



Royal Anthropological Institute, April 20. — Prof. W. 



Ridgeway, president, in the chair. — The Blackfeet Indians 

 of Montana : W. MacClintock. The author has an 

 intimate acquaintance with these Indians, having beeri 

 adopted as son by Mad Wolf, one of the chiefs. The 

 Indians were shown in their great summer encampment 

 on the plains, and views were given of many of the lodges. 

 These are all painted with various symbols of great 

 interest, the heavens being usually shown at the top of 

 the lodge, and the earth at the bottom, with various 

 sacred animals in the middle. One of the lodges was 

 painted with a pictorial description of the owner's victories 

 and achievements, as also was the chief's war-horse. The 

 great feature of this summer camp was the sun ceremony, 

 for the tribe believes that it is descended from the sun 

 and moon, whose grandchild, the son of the morning 

 star, was sent down to earth. A spotless woman is the 

 chief of the festival, and on arrival at the chosen place 

 this woman, with her attendants and priests, fasts and 

 prays for four days, during which time the other inmates 

 of the camp amuse themselves with mimic warfare and 

 games. On the third day the woman proceeds to a spot 

 already selected, and offers a meat offering of buffalo 

 tongues. On this spot the sun tent, a simple erection of 

 poles, is erected, and after it has been blessed by the holy 

 woman it becomes the central point of all the subsequent 

 ceremonies. These consist of games, acting, and the 

 recitation of their deeds of valour by the chiefs. The 

 ceremonies conclude by the chief priest wishing the tribe 

 prosperity during the coming year. 



Royal Meteorological Society, April 21. — Mr. H. 

 Mollish, president, in the chair. — Percolation, evapora- 

 tion, and condensation : Baldwin Latham. The author 

 gave the results of the observations which he had carried 

 out at Croydon on these subjects during the last thirty 



