March 14, 1889] 



NATURE 



477 



observed at lower levels than Zermatt and the Riffel, but with 

 even less intensity. On the last occasion (November lo, 1884) 

 that such an observation was recorded, there was only a trace of 

 these faintly seen. No doubt a clear atmosphere, free from the 

 turbidity so easily created by condensing moisture, is essential to 

 their visibility. Schoene has observed bands in a bright sky 

 before sunrise and after sunset, during an intense frost in Central 

 Russia. The measurements taken identified them with ozone 

 bands, and leave scarcely any doubt whatever of the presence of 

 ozone in the atmosphere, and if it can be so recognized, it must 

 communicate its characteristic blue colour to the air (Journ. 

 Chem. Sec. Abstracts, vol. xlviii. part 2, p. 713). The remark- 

 able crepuscular phenomena seen at the close of 1883 proved 

 highly favourable to such investigations. 



In order to continue a series of observations on the solar 

 spectrum near D it would be best to employ a fairly good dis- 

 persion and large lenses with long focus admitting a large amount 

 of light to the eye, or, better still, to specially prepared photo- 

 graphic plates highly sensitive to the yellow rays. 



The very extensive absorption of the ultra-violet rays by 

 oxygen leads us to expect it to be fluorescent. All such ab- 

 sorbents are fluorescent more or less, and generally strongly, but 

 when the absorbed rays are of very short wave-length the fluor- 

 escence is not always visible. Thus there are many substances 

 which do not appear fluorescent by lime-light nor by dull daylight, 

 but are strongly so when seen by electric light, especially if it has 

 passed ihrough no glass or other medium than a quartz lens and a 

 short column of air. Some substances are not fluorescent when 

 seen in glass vessels, because the glass has absorbed those rays of 

 which the refrangibility would have been lowered by the fluor- 

 escent substance. In air, and by the light of an electric spark 

 rich in ultra-violet rays, such as that from cadmium electrodes, 

 almost everything is fluorescent. The whole range of the 

 cadmium spectrum has been viewed by me, owing to the fluor- 

 escence of the purest white blotting-paper. The light, of course, 

 is feeble, and the eye has to be trained to make observations 

 in'total darkness. 



Pure water, however, never appears fluorescent. Some solu- 

 tions in water, which transmit all the ultra-violet rays as far as 

 2304, are fluorescent, though whether this is caused by impurities 

 or not has not been decided. 



It cannot any longer be doubted (i ) that the extreme limit of the 

 solar spectrum observed by Cornu is caused by the gases in the 

 atmosphere, probably both by oxygen and ozone ; (2) that the 

 blue of the sky is a phenomenon caused by the fluorescence 

 of the gaseous constituents of the atmosphere, and probably 

 ozone and oxygen are the chief fluorescent substances; (3) 

 that ozone is generally present in the air in sufficient quantity 

 to render its characteristic absorption-spectrum visible, and that 

 therefore it gives a blue colour to the atmosphere by absorption, 

 through which blue medium we observe distant views ; (4) that 

 water vapour does not participate in the coloration of the 

 atmosphere under like conditions and in the same manner as 

 ozone. W. N. Hartley. 



Royal Coll ege of Science, Dublin. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Cambridge. — The Vice-Chancellor of Cambridge University 

 publishes the following : — 



^' Ferndene, Gateshead, March ^, 1889. 



"Sir, — You maybe aware that some years ago I erected 

 here a refracting telescope, 25-inch aperture and 30 feet focal 

 length. 



.. " Owing to unfavourable atmospheric conditions and other 

 reasons, the instrument has done no systematic work in its pre- 

 sent position. I should much like to place it where it would 

 work under capable direction. 



"I contemplate offering my telescope and the dome and 

 i istruments connected with it to the University of Cambridge. 

 The part that the University has taken of late years in the 

 advancement of science induces me to hope that the possession 

 of an instrument especially adapted to the study of stellar 

 physics may give impetus to the development of the subject. 



"I beg you therefore to give the matter consideration, and 

 let me know what proposals can be made to insure proper use 



and maintenance of the instruments, and publication of yearly 

 ^eports, in case my offer is acceptable to the University. 

 "I have the honour to be, Sir, 



" Your obedient Servant, 



"R. S. Newall. 

 " The Vice-Chancellor of the University of Cambridge." 

 At the Congregation to-day, at 2 p.m., the following Grace, 

 having received the sanction of the Council, is to be offered to 

 the Senate : — 



" That the Vice-Chancellor, Dr. Routh, Dr. Glaisher, Prof. 

 Adams, Prof. Liveing, Prof. Darwin, and Prof. Thomson, be 

 appointed a Syndicate to consider Mr. R. S. Newall's munificent 

 proposal to present his telescope to the University, and the 

 arrangements and expenditure which would be necessary to 

 maintain and utilize it for astronomical and physical research, 

 and to report to the Senate." 



SCIENTIFIC SERIALS. 



In ^^ Journal of Botany for February and March, Mr. A. 

 Fryer continues his notes on pond-weeds, the present instalment 

 being characterized by two plates and the description of a new 

 species, Potamogetonfakatus, from Huntingdonshire. Another 

 addition to the British flora is recorded by the Rev. E. S. Mar- 

 shall, in Festuca heterophylla, from Witley, in Surrey ; and Mr. 

 F. J. Hanbury describes no less than four species or sub-species 

 of the difficult genus, Hieracium, new to science — all from the 

 extreme north of Scotland. Messrs. G. Murray and L. A. 

 Boodle commence a monograph of Avrainvillea, a genus of 

 siphonocladaceous Algse, which they consider most nearly allied 

 to Penicilhis and Udotea. 



lLi{% Botatiical Gazette for January contains a short description 

 and history, illustrated by five plates, of the new Botanical 

 Laboratory at the University of Philadelphia. The occurrence 

 of a new phosphorescent Fungus is noted, Agaricus {Clitocybe) 

 illudens, in which the phosphorescence appears to reside in the 

 hymenium. In the number for February, Dr. Henrietta E. 

 Hooker gives a highly interesting description of the structure and 

 mode of life of the common dodder of Massachusetts, Cuscuta 

 Gronovii. It is stated to have a habit of entirely withdrawing 

 its roots from the soil by the contraction of the coils of its twin- 

 ing stem as soon as it commences to lead a parasitic life on its 

 host. Miss Emily L. Gregory continues her paper on the 

 " Development of cork-wings on certain trees." 



Rivista Scientifico- Industriale, January 31. — On the oxalate 

 of lime in plants, by Prof. Aser Poll. In these remarks, which 

 are made in connection with C. Acqua's recent contribution to 

 the study of the crystals of the oxalate of lime in plants, it is 

 argued that even on Acqua's own showing, the presence of these 

 crystals cannot be regarded as necessary to the life of the plant. 

 In some they are not found at all, and where they do exist they 

 seem to be rather an inevitable consequence of the production 

 of oxalic acid in the presence of the salts of lime. — Prof. Ercole 

 Fossati continues, without concluding, his elaborate monograph 

 on the thermic and electric properties of iron subjected to 

 magnetic influences. 



Bulletin de la Sociit^ des Naturalistes de Moscou, 1888, No. 3. 

 — On the peculiarities of the skulls of the homed cattle of 

 the Kalmucks, by P. Kuleschoff (in German), with photographs 

 of skulls. The great likeness between the skulls of the 

 Kalmuck race of horned cattle and those of Bos sondaicus and 

 the zebra brings the author to the conclusion that the ancestors 

 of the European cattle must be searched for in India. — On the 

 Orthopteres of Crimea, by O. Retowski (with three plates). — 

 On the structure of the pseudo-scorpions, or Chernetida, by A. 

 Croneberg (both in German). The differences in the structure 

 of this group and that of the scorpions proper are pointed out, 

 and Thorell s views on the affinities of the Chernetida are con- 

 firmed. — Review of the generative organs of the Pompilida, by 

 General Radoszkowski (in French, with four plates). — Supple- 

 mentary note on the great comet 1887 I., by Th. Bredichitv 

 (in French). It belongs to the author's third class of comets — 

 that is, it consists of heavy elements ; and more accurate calcula- 

 tions convince the author that it could consist only of elements 

 having a great molecular weight, such as gold, mercury, and 

 lead. — Some additions to the flora of Moscow, by S. Milutin. 



