December 21, 191 1] 



NATURE 



261 



equatorial and the polar zones are inefficient as compared 

 with the middle latitude : this result is produced by the 

 unequal distribution of cirrus clouds, which are the effective 

 factors in determining the outgoing radiation ; (2) where 

 d is the depth of the water layer in millimetres, and e the 

 partial pressure of the water vapour in millimetres of 

 mercury, the thickness that WQuld accrue if all the water 

 vapour above any given level in the atmosphere, on cloud- 

 less days, were condensed, is expressed approximately by 

 i = ie; this is some 13 per cent, less than the value, 

 Hann's, heretofore commonly employed in bolometric work. 



The reality of astronomical teaching in America was well 

 illustrated by a thoughtful paper by Prof. Sarah F. Whiting, 

 in which she urged the importance of daytime laboratory 

 work in astronomy. 



Prof. Very explained an attempt to form a standardised 

 scale of intensities for the lines in the solar spectrum, and 

 Miss Leavitt contributed a paper on the variable stars in 

 the Small Magellanic Cloud ; the stars are too faint for our 

 present spectroscopic equipments, but the spectroscopic in- 

 vestigation of brighter stars having similar light-curves — 

 e.g. UY Cygni — might prove very profitable. Prof. S. A. 

 Mitchell described the radial velocities of 96 Herculis, which 

 has four components, all measurable on some plates ; the 

 velocities range from —98 to -h74 km. per sec. and the 

 period is 502 days. 



Prof. Tucker's description of the San Luis Observatory 

 of the Carnegie Institution produces a feeling somewhat 

 akin to envy for the facilities afforded by such an institu- 

 tion. The expedition left New York in August, 1908, and 

 six months later the observatory and a dwelling for the 

 ten observers were completed. Observations with the Pistor 

 and Martins meridian circle of the Dudley Observatory were 

 commenced in April, 1909, and 87,000 observations were 

 completed when the work was brought to a close in January 

 this year ; the reductions will be completed at the Dudley 

 Observatory. 



The preliminary work done at the Dominion Observatory, 

 sharing in the international cooperative scheme, on the 

 rotation of the sun was explained by Mr. Plaskett. The 

 mean of twenty-three plates taken during June and July 

 this year gives an equatorial velocity of 2-034 ±0-004 km., 

 the probable error of a single plate being ±0-017 km. ; all 

 the elements represented between \ 5500 and \ 5700 appear 

 to share in a common velocity. 



Halley's comet was the subject of papers by Prof. 

 Barnard and Prof. Frost, respectively, the former giving the 

 preliminary results determined from Mr. Ellerman's photo- 

 graphs taken at Hawaii, the second finding -I-55 km. per 

 sec. as the radial velocity of the comet on May 24, 1910, 

 this value was obtained from measurements of the displace- 

 ments of the Fraunhofcr lines, and agrees, within i km., 

 with the value given by the ephemeris. 



Dr. Slocum described the spectroscopic effects produced 

 by the large solar prominence of October 10, 19 10. The 

 prominence rose to a height of 105,000 km., and the local 

 relative displacement of the absorption and emission lines 

 represented a radial velocity of 15 km. per sec. Dr. O. J. 

 Lee finds that, for reversal, the lines \ 4427 and H (\ 3968) 

 require vapour densities one-seventh and 1-5 times as great, 

 respectively, as that necessary for the reversal of K, when 

 the vapour is observed at 2500° C. and at atmospheric 

 pressure. 



Prof. S. I. Bailoy discussed the magnitudes of the stars 

 in the cluster Messier 3. the discussion being based on a 

 photograph, taken by Ritchey with the 60-inch reflector, 

 showing some 30,000 stars down to magnitude 21-5: the 

 total light of 2542 stars the magnitudes of which were 

 deterrnined is approximately equal to that of a star of 

 magnitude 10-4. Dr. Albrecht reported on his work in 

 determining the effective wave-lengths of lines in various 

 types of stellar spectra, and also reported the results secured 

 in a determination of the definite wave-lengths of the 

 silicon lines at \\ 4552-7, 4567-0, and 4C74-9 in stellar and 

 in laboratory spectra. His stellar values are 4552-762, 

 4567-067, and 4574-918 respectively, and these are compared 

 with similar values obtained by Gill and McClean, and 

 laboratory values secured by Exner and Haschek, Frost and 

 Brown, Lockyer, and Lunt. Ho emphasises the necessity 

 for more laboratory work in order to investigate the causes 

 producing the present lack of close agreement. In a third 



NO. 2199, VOL. 88] 



paper the same worker directs attention to the grave 

 importance of investigating the change of wave-length of 

 fundamental lines in passing from one spectral type to 

 another. Such differences might, inter alia, account for 

 certain systematic errors in the wave-length of the B type 

 stars, and the elimination of these errors might directly 

 affect the position of stars of this type in any discussion of 

 the structure of the universe. 



The list of papers concluded with one by Dr. Russell 

 dealing with the photographic determination of the moon's 

 position, a note on the five EUicott astronomical instru- 

 ments which were constructed about 1780-90 and are now 

 on view in the U.S. National Museum, and a report from 

 the committee on photographic astrometry. The resolutions 

 of the latter strongly express the opinion that photographic 

 methods can be applied successfully to absolute, as well as 

 to differential, determinations of star positions, thereby 

 gaining the advantage of independent observations with 

 instruments of entirely different characters. 



BIOMETRICIANS AS ANTHROPOLOGISTS. 



T T is only necessary to turn to the current issue of 

 -*■ Biometrika ^ to see the extent to which modern bio- 

 metricians are devoting themselves to anthropology. About 

 two years ago Dr. Crewdson Bennington died, leaving 

 behind him a mass of observations and notes he had made 

 in connection with the biometrical laboratory of University 

 College. Prof. Pearson has systematised Dr. Bennington's 

 observations and notes, and with the help of other workers 

 in his laboratory brought Dr. Bennington's work to com- 

 pletion. 



Dr. Bennington's aim was to obtain type-contours of the 

 skull and of the living head of various races of mankind — 

 contours which might serve as racial types. For instance, 

 exact tracings were made in three planes of 100 crania of 

 ancient Egyptian men. These contours were plotted out 

 and combined by a method suggested by Prof. Pearson, and 

 in this manner type contours were obtained for the ancient 

 Egyptians of the twenty-sixth and thirtieth dynasties. 



The results which interest us most are those contours 

 prepared from the Whitechapel plague-pit skulls (seven- 

 teenth century) and those made from the heads of 118 men 

 of the Royal Engineers of the present day. When these 

 ancient and modern forms are compared, Prof. Pearson 

 finds that there is no reason to believe that there is " any 

 substantial difference between the English head of to-day 

 and our plague-pit crania, which we have been told are 

 not typical English." The editor of Biometrika has issued 

 with this paper copies of Dr. Bennington's type-contours 

 on transparent paper, so that they can be utilised by other 

 workers for purposes of comparison. 



Besides the important paper just noted, in parts i.-ii. 

 of Biometrika there are others which will prove of value 

 to the student of mankind. Dr. David Macdonald's inquiry 

 seems to show that the acute infections of childhood favour 

 the children with dark skin and eyes; they survive the 

 effects of infection better than children with fair skin and 

 blue eyes ; the dark-skinned children are therefore being 

 preserved or selected. Dr. Schuster's observations on the 

 undergraduates of Oxford show that the students there have 

 longer and narrower heads than those at Cambridge or at 

 Aberdeen. The Oxford men are also considerably taller. 

 Another important anthropological paper in the same 

 number is Mr. J. I. Craig's " Anthropometry of Modern 

 Egyptians." 



ROCK CRYSTAL: ITS STRUCTURE AND 



USES.^ 



ROCK crystal, quartz, the common crystallised form of 

 dioxide of silicon SiO,, is, from many points of 

 view, the most interesting of all minerals and the most 

 instructive example of crystalline structure known to us. 

 "What is a crystal?" The evidence is now overwhelm- 

 ingly complete that a crystal is a homogeneous structure 

 built up on the plan of a space-lattice, each of the unit 



1 Biometrika, parts i. and ii., July, 1911. Edited by Prof. Karl Pearnon. 

 Price aar. net. ... l n i c • 



'•2 From four Cantor I ectures delivered in May, 1911, to the Royal Society 

 of Arts by Dr. Alfred E. H. Tutton, F.R.S. 



