292 



NATURE 



[October 28, 1920 



are listed, ranging in power consumption from 700 to 

 9500 watts. The muffles are made of a new refrac- 

 tory material called "Ameroid," which is claimed to 

 possess special advantages. We would suggest that 

 intending purchasers of furnaces would prefer to know 

 the composition of the refractory — to which the name 

 given furnishes no clue — so as to judge of its suit- 

 ability to their requirements. 



Engineering for October 15 contains a description 

 of a new 7J-ton six-wheel commercial vehicle made 

 by Messrs. G. Scammell and Nephew, London. One 

 obvious way of reducing costs of road transport is 

 to increase the weight of the load which can be 

 handled by one vehicle and one road crew, and this 

 lorrv appears to fulfil this condition admirably. It 

 consists of a four-wheel chassis carrying the engine, 

 and is arranged to draw a two-wheel body which 



pivots on a turntable at the rear of the chassis. The 

 weight of the complete vehicle is 44 tons, and it can 

 carry a load of 74 tons without exceeding an axle-load 

 of 6 tons, which is the limit allowable for a vehicle 

 travelling at 12 miles per hour. The vehicle is able, 

 in addition, to draw a 6-ton trailer, so that a useful 

 load of 13J tons can be dealt with. Whilst the 

 vehicle is not the first six-wheeler which has been 

 produced, it possesses many points of novelty and 

 interest which add to its usefulness and efficiency. The 

 engine develops 47 brake-horse-power at 1000 revolu- 

 times per minute. 



The presidential address to Section H (.Anthropo- 

 logy) of the British .Association, which was delivered 

 by Prof. Karl Pearson at Cardiff in .August last, has 

 been re-issued as a separate publication by the Cam- 

 bridge University Press, price is. 6d. 



Our Astronomical Column. 



Brilliant Meteor of October 19.— This fine object 

 was observed at 8.15 G.M.T., and descriptions of its 

 appearance have been received by Mr. Denning from 

 Purley and Oxted, in Surrey, and from Stowmarket. 

 Fortu'natelv, the meteor was seen by two experienced 

 observers, 'Miss A. Grace Cook and Mr. J. Edmund 

 Clark. It was brighter than Venus and gave .-n 

 inten.se flash, although the half-illuminated moon 

 was in the same quarter of the sky. The motion 

 was moderate, and a streak remained along one 

 section of the path for about 10 seconds. 



On the same date as that on which the meteor 

 appeared the shower of Orionids is usually abundant, 

 and the fireb.ill from its direction of flight seems to 

 have been a brilliant member of that system, though 

 the radiant point was a few degrees below the horizon. 



If we adopt a radiant at 88-+ 17°, the observations 

 of the object indicate a height from about 6t to 

 69 miles along a path of 110 miles, and a velocity of 

 about 35 njiles per second. In fact, the meteor seems 

 to have been rising in the atmosphere instead o^ 

 falling, as is usually the case. 



The luminous flight occurred over the English 

 Channel, from close 10 Beachy Head to about 40 miles 

 south of Bournemouth. 



Over the West of England the sky was cloudy, and 

 it is important that further accounts should be sent 

 to -Mr. Denning from the eastern counties, as the 

 computed heights are rather exceptional and require 

 further investigation. 



The Total Solar Eclipse of September, 1922. — 

 The track of totality in this eclipse traverses the 

 Maldive Archipelago and Christmas Island, south of 

 Java. It then passes right across Australia, but 

 reasonably accessible stations are confined to the eastern 

 portion of its track. Mr. H. \. Hunt, the Common- 

 wealth Meteorologist, acting under instructions from 

 his Government, has prepared a map giving much 

 meteorological information. 



A shaded area runs across .Australia parallel to, but 

 somewhat south of, the eclipse track ; it is stated that 

 this shaded region has no single well-marked wet 

 season, but is subject to both summer and winter 

 rain-producing influences. The map also shows the 

 periods in which most rain falls in each region, and 

 it is noteworthy that the month of September occurs 

 in the wet season on the south coast only, so that 

 the month appears to be favourable on the eclipse 

 track. Thy sun's altitude on the east coast of Queens- 

 land is only 18°, but 26° may be obtained by pro- 

 NO. 2661, VOL. 106] 



ceeding inland by rail to Cunnamulla or Coongoola. 

 The directors of the leading Australian observatories 

 have expressed their hope of occupying stations \n 

 Queensland, while plans are being formed for expedi- 

 tions from England to the Maldives and Christmas 

 Island. The scheme of observations will include 

 further verification of the gravitational deflection of 

 light, as it is desirable to strengthen the evidence for 

 a result of such fundamental importance. 



The Capture of Comets by Planets. — Prof. H. N. 

 Russell contributes a second article on this subject 

 to Astr. Journ., No. 775. He shows that out of a 

 hundred million comets that approach within an astro- 

 nomical unit of the sun, 90,000 would be made 

 periodic by Jupiter's action and 2400 by that of Saturn, 

 while the numbers in the case of Uranus and Neptune 

 are only 14 and 8 respectively. Hence he concludes 

 that the two outermost planets have not played anv 

 part in such capture, with the possible exception of 

 the comet of the November meteors by Uranus. Prof. 

 Russell admits the curious relationship of the orbits 

 of the comets with periods less than a century, which 

 fall into four groups, the aphelia of which are some- 

 what outside the orbits of the giant planets. This 

 point gives strong grounds for assuming some con- 

 nection between these cometary groups and the cor- 

 responding planets ; further, the point made by Prof. 

 Russell, that many of the cometary orbits considered 

 do not pass within several astronomical units of the 

 planet with which they are associated, may be ex- 

 plained by the slow alteration in the cometary orbit 

 through planetary perturbations. 



Many of the facts now pointed out were noted by 

 Mr. R. lA. Proctor half a century ago. His explana- 

 tion .was that the origin of the comets in question 

 took place, not by capture, but by expulsion from the 

 giant planets. It is surprising that this suggestion 

 has met with so little support from other astro- 

 nomers ; the phenomena observed in the atmospheres 

 of Jupiter and Saturn testify to the existence of very 

 powerful forces. Even on the earth such explosions 

 as that of Krakatoa occur, in which cubic miles of 

 matter are flung to a great height. Moreover, retro- 

 grade orbits would occur more readily if the motion 

 of the parent planet were slower and its gravitation 

 weaker, which would explain their restriction to the 

 comet-families of Uranus and Neptune. Hence it 

 would seem to be premature to accept the non- 

 connection of Neptune with the comet-family thai 

 bears his name, as finallv demonstrated. 



