July 13, 1876] 



NATURE 



231 



pools, which become ponds in dry weather. This northern 

 country opposite to Greenland has been "carved" in this 

 fashion by ice on the large scale, and afterwards by water- 

 streams, and by the frequent falling of rain drops. It has 

 also risen from the sea. The ice-cover has been taken off 

 Scandinavia and Finland, and there it is possible to test 

 theories about the work which an ice- cover is now doing on the 

 present chief gathering grounds of snow throughout the world. 

 But that Scandinavian work is the same kind of work which is 

 found with small glacial marks elsewhere. Hollows have 



rounded sections ^^ ^, or when deep they are like U' Hills 



between hollows commonly are hog-backs .-— v , and generally 

 the land is rounded, except where peaks rise, and cliffs have 

 broken. But this kind of rounded sculpture exists only in some 

 regions cf the world, and it marks the site of local glacial 

 periods, as I believe. Elsewhere the section of valleys is angular 

 like V» or in canon countries like Y- These angular grooves 

 are known to be the work of streams, because every stream of 

 water carves on the same plan. Rounded hills and dales are 

 at first sight evidence of powerful ice erosion, but some kinds of 

 rock weather in bosses. If it be admitted that a drop wears a 

 stone, that a stream makes a deep cation in a long time, and that 

 a glacier "abrades "or makes any mark at all, it seems to follow 

 that an ice-engine as large as India or Scandinavia has in fact 

 done the large work which it might be expected to do by perse- 

 verance in working, as it is known to work, wherever snow now 

 gathers in large masses. Given the hardly perceptible wearing 

 of water and time, a cation a mile deep and many hundreds of 

 miles long has resulted from the flowing of a stream. Given 

 glacial "abrasion" and time enough, than valleys of rounded 

 section, and firths and lake-basins of a particular kuid probably 

 resulted from the flowing of ice. 



There are plenty of hollows in the earth's surface which are 

 not the result of erosion but of other causes with which I am not 

 now concerned. Where a stream flows from source to mouth on 

 a gradual slope, there has been no great disturbance of level since 

 the stream began to work. Where ice fills the dales there are no 

 canons. Where ice has filled dales and has left fresh marks, 

 canons are short and small. In mountain regions where ice- 

 marks are rare or absent, canons are of great depth and length, 

 apparently because their streams have flowed in the same 

 channels ever since the mountains were raised. But where 

 canons are marked features, these lakes, firths, and dales of 

 rounded section are very rare, or do not exist. It seems there- 

 fore that hoUows which have, in fact, been carved out of the 

 earth's surface may be known for water- work, or for ice-work by 

 their shape, and that firths, dales, and lakes may mark the sites 

 of local glacial periods ; and cations the sites of climates that 

 have not been glacial since the streams began to flow. Persever- 

 ance may accomplish great results insensibly like ice in dales, 

 water in water-courses, and drops on stone. 



Let me counsel those who wish to study the works of ice on a 

 large scale to abandon the retiring glaciers of Switzerland and 

 study Nature in Norway. This is the best season for travelling 

 there. J- C. 



June 23 



The Loan Scientific Collection at South Kensington 



As a science teacher, privileged to attend the special demon- 

 strations upon the extraordinary assemblage of apparatus now 

 filling the galleries of the exhibition buildings, a list of some of 

 which appeared in last week's Nature, would you allow me 

 to call attention to the provision of the department by which the 

 general public may be admitted, if room, at a nominal charge. 



Within the past few days my note-book shows that the original 

 instruments of Sir Isaac Newton, Faraday, Fizeau, Wheatstone, 

 Watt, Savery, Black, Cavendish, Guericke, and others employed 

 in their classic researches, have been shown and explained (and 

 used, so far as experimentalists would presume to touch such 

 now almost venerated relics). 



The spacious and well-appointed lecture-theatre has not been 

 always crowded ; but I have the impression that if the above 

 regulation were widely understood there would be such a 

 gathering, not of the merely curious, who would attend as at an 

 entertainment in natural magic, but of those deeply interested in 

 the topics discussed, as would prove too large for the accommoda- 

 tion at present provided ; and, whilst scientific enrichment of 

 the public would be more largely secured, a compliment would 

 at the same time be paid to the directors for their great efforts to 

 promote the success of this important undertaking. 



The School of Science, July 6 William Gee 



Evolution of Oxygen by "Vallisneria Spiralis" 



Have any of your readers noticed the rapid evolution of 

 oxygen by a blade of Vallisneria spiralis ? If a blade is cut or 

 broken and held under water, the bubbles of gas are rapidly 

 noticed issuing from the broken end, and by a simple arrange- 

 ment of placing the broken blade or several blades into a test 

 tube filled with water the water is displaced and the gas col- 

 lected. After forty-eight hours the pores of the broken end of 

 the blade close up and a fresh fracture is necessary to restore the 

 evolution of gas, which also ceases at night only to recommence 

 when the sunlight reappears. I have collected about a cubic 

 inch of gas in eight hours from one blade of the plant. A con- 

 firmation of my experiment would please me. 



Stroud, July 3 Walter J. Stanton 



Stamens of Kalmia 



If the beautiful spring trap formed by the stamens of the 

 Kalmia, by which insect fertilisation is secured, has not yet been 

 noticed, I may perhaps be allowed to call attention to it 



Cahirmoyle, Ardagh, Co. Limerick C. G. O'Brien 



Optical Phenomenon 



For more than half an hour after sunset this evening there was 

 a broad band of light rising vertically through a clear sky imme- 

 diately above where the sun had set. It moved as the sun moved 

 northward below the horizon, retaining its vertical position. It 

 must have been formed at a very great height in the atmosphere, 

 fer it outlasted all the other sunset tints, which were very beau- 

 tiful. It would be interesting to know whether this was seen 

 from many places far apart. Joseph John Murphy 



Old Forge, Dunmurry, Co. Antrim, June 27 



The Cuckoo 



With regard to the letter of Mr, Adair, in last week's Nature, 

 p. 210, on the cuckoo, I have only to observe that if it does not 

 sing in Somersetshire after Midsummer it does /lere, in Middle- 

 sex ; I heard it, to my astonishment, early in the morning of the 

 6th inst., in the woods and hills to the north. I never recollect 

 its note so late, not after the 3rd. 



Harrow, July 10 Henry St. John Joyner 



OUR ASTRONOMICAL COLUMN 



Short's Observation of a supposed Satellite of 

 Venus. — This observation which, as it appears in the 

 Philosophical Transactions, vol. xli. (Nature, vol. xiv., 

 p. 194), is mystified by a typographical error, is also found 

 in " Histoire de I'Academie des Sciences, 1741," p. 125, 

 where the micrometrically-measured distance of the sus- 

 picious object from Venus is given in what seems to be a 

 more correct form, and as it was used by Lambert in his 

 calculations. After referring to the observations of the 

 elder Cassini in 1672 and 1686, the writer — probably 

 Cassini II., author of "Elemens d'Astronomie " — states 

 that Mr. Short had again seen the satellite, real or appa- 

 rent, in the preceding year (1740), under similar circum- 

 stances, and with the same phase as Cassini had described ; 

 he had been informed of this in January, 1741, by M. 

 Coste, " auteur de la Traduction du livre de I'Entende- 

 ment Humain de Locke, et de plusieurs autres ouvrages ;' 

 and having communicated the observation to the Academy 

 of Sciences, had been charged by that body to inquire 

 more particularly concerning it, and report the resulf. 

 But as Short had not seen the satellite again up to June, 

 1 74 1, nothing further was ascertained than had been 

 notified in the letter addressed to M. Coste, which was 

 from " Mr. Turner, written from London, June 8." 



Short's observation was " made in London, November 3, 

 1740, in the morning, with a reflecting telescope of 16^- 

 English inches, and which magnified the diameter of the 

 object from fifty to sixty times. He perceived at first 

 what appeared to be a small star ver>' near to Venus, 

 upon which, having applied to his telescope a stronger 

 eyepiece and a micrometer, he found the distance of the 



