94 



NATURE 



March 27, 1913 



of the pole and that given by tidal terms of long 

 period. Consideration of the effects of ocean tides 

 (discussed according to the dynamical theory) upon 

 the semi-diurnal deformation of the solid earth gives 

 the value for the rigidity of the earth as being two 

 or three times that of steel. This value is of the same 

 order as is required to account for the observed 

 wandering of the pole, and also for the diurnal tide 

 in the solid earth. Dr. Schweydar does not set much 

 store by Dr. Hecker's differing results for the values 

 of the east-west and the north-south elasticity, and he 

 gives reasons for not accepting the explanations 

 offered by Hecker and Lallemand. On one other 

 debatable point of much importance Dr. Schweydar's 

 results will be read with much interest. If the earth 

 is to be regarded as consisting of an elastic core, a 

 viscous layer, and a rind, then he decides that this 

 viscous layer cannot be supposed to be of the fluidity 

 of molten metal, but must be regarded as to all prac- 

 tical purposes solid. It need scarcely be stated here 

 that this was the view reached on quite other grounds 

 by the late Sir George Darwin. 



In two papers published in the Atti R. Accad. Lincei 

 (vol. xxxi., ii., pp. 740 and 803) Profs. R. Nasini and 

 C. Porlezza describe the discovery for the first time 

 of ozone in a natural water, and discuss the possible 

 reasons for its presence therein. The water is that 

 of Le Bagnore of Santa Fiora, in Monte Amiata, and 

 the ozone is not a transitory but a permanent and 

 normal constituent, imparting a distinct odour to the 

 water, and being present to the extent of about 

 015 c.c. per litre. The water is not radio-active, and 

 in default of other possible explanations, the view is 

 put forward that the presence of ozone is due to 

 autoxidation of ferrous bicarbonate, either per se or 

 brought about by the action of the so-called iron- 

 bacteria. The water of a spring at Bagnoli, Arci- 

 •dosso, also in the Monte Amiata district, possesses 

 similar properties, but in a minor degree. Both these 

 waters have locally a high therapeutic reputation, and 

 the question arises whether this is due to the ozone 

 which they contain. Further investigations will be 

 made to decide this and other points as to which there 

 is still some uncertainty. 



We have received a copy of the Transactions of the 

 English Ceramic Society, part ii., session 1911-12, 

 which, in addition to a number of papers of technical 

 interest to potters, contains an account, which is of 

 more general interest, of several of the principal 

 pottery works on the Continent. In the summer of 

 1912 members of the Ceramic Society made a tour of 

 inspection of ceramic works in Holland, Germany, 

 and Belgium, and a report of the visit, admirably 

 illustrated by photographs, covers forty pages of the 

 Transactions. The descriptions given of the Royal 

 Berlin Porcelain Factory at Charlottenburg, founded 

 b'- Frederick the Great in 1763, and now carried on 

 by the Prussian Government, with 660 workmen, and 

 of the Royal Porcelain Factory at Meissen, founded 

 in 1710, and now employing 800 hands, are of par- 

 ticular interest. The writer of the report expresses 

 regret that no such institutions exist in England : — 

 " In Germany, should a manufacturing potter have 

 NO. 2265, VOL. 91] 



an idea which, through lack of capital or initiative, 

 he is unable to work out to fruition, he at once has 

 the assistance of the State pottery to test, and, if 

 necessary, to evolve that idea, whereas in England 

 brains can only be utilised apparently to the accom- 

 paniment of capital and risk." 



A memorial portrait of the late Capt. Scott in 

 uniform has been published by Messrs. Maull and 

 Fox, the proprietors of the copyright in the only photo- 

 graphs of the explorer in full-dress uniform. The 

 portrait, which is a photogravure, has been approved 

 by Lady Scott, and the publishers have undertaken 

 to contribute an agreed proportion of the profits of 

 the sale of the portrait to the National Fund which 

 is being raised. The price of the portrait is 55. each, 

 and copies can be obtained through the usual trade 

 channels, or from Messrs. Maull and Fox, 187 Picca- 

 dilly, London, W., or Messrs. S. Hildesheimer and 

 Co., Ltd., 96 Clerkenwell Road, London. 



OUR ASTRONOMICAL COLUMN. 



Spectrum of the Pleiades Nebula.— Bulletin No. 55 

 of the Lowell Observatory contains an interesting 

 account of the results secured by Mr. Slipher in the 

 photography of the spectrum of the nebula in the 

 Pleiades. This nebula, as Mr. Slipher points out, 

 would doubtless naturally be classed as a gaseous 

 nebula since in its prominent characteristics it re- 

 sembles more the great nebula in Orion, the typical 

 gaseous nebula, than the more numerous class of 

 spiral nebute. However, with the 24-in. refractor of 

 the Lowell Observatory he made an exposure of 

 twenty-one hours, obtaining, as he states, a perfectly 

 legible record. This spectrum was continuous and 

 crossed by strong hydrogen lines, H/3, H7, H5, He, 

 and Hf, and fainter helium lines, those at 4026, '4381^ 

 and 4472 (combined with 4481) being recognisable. 

 No trace of any of the bright lines seen in the spectra 

 of gaseous nebulae was found, but the spectrum re- 

 sembled a copy of the brighter stars of the Pleiades. 

 The result suggested that the spectrum might be due 

 to light from Merope scattered and reflected by the 

 large objective. Exposures on the nebula of Orion 

 and of a region near Sirius, led him to conclude that 

 "the nebula shines by light, the spectrum of which 

 is a true copy of that of the neighbouring star Merope 

 and of the other bright stars of the Pleiades." It is 

 suggested then that the nebula is disintegrated matter 

 similar to what we are acquainted with in our solar 

 system, as in the rings of Saturn, comets, &c, and 

 that it shines by reflected light. 



Chromospheric (Solar) Lines in the Spectrum of 

 $ Persei. — An interesting paper bv Mr. Paul W. 

 Merril forms part of Lick Observatory Bulletin 

 No. 224. In the course of a survey of Class B stars 

 having bright hydrogen lines, the author has measured 

 a number of lines, bright and dark, between ^4340 

 and 6515 in spectrograms of this star, and connects 

 these lines with "chromospheric" lines taken from 

 Young's lists in Frost-Scheiner's "Astronomical 

 Spectroscopy." It is to be regretted that the author 

 has not employed a more recent authority. However, 

 he considers the presence of "chromospheric" radia- 

 tions in the stellar spectrum established. The star 

 does not duplicate the solar chromosphere, for it is 

 stated that the phenomena presented by helium, mag- 

 nesium, and sodium are anomalously at variance with 

 the chromospheric spectrum. This paper extends and 

 confirms, apparently unconsciously, the conclusion 

 previously arrived at bv Sir Norman Lockver and 



