302 



NA TURE 



[July 27, 1905 



In the course of a paper published in the June number 

 of the American Naturalist on the advantages presented 

 by the common sl<ate as a subject for demonstration to 

 anatomical classes, Dr. H. W. Rand takes occasion to 

 emphasise the importance of selecting generalised, in place 

 of specialised, species for such demonstrations. A skate 

 or a dog-fish is thus to be preferred to a bony fish, and 

 similarly a salamander to a frog. As regards the choice 

 between a skate and a dog-fish, although the former is a 

 much more specialised type than the latter, it has the 

 advantage of being more easily obtained and of being 

 available for the greater part of ihe year. Moreover, its 

 very specialisation happens to be an advantage to it as an 

 object for demonstration, for not only does its flattened 

 form render it admirably suited for dissection, but most 

 of its organs are brought more or less nearly into one 

 horizontal plane, so as to be capable of demonstration 

 almost as if drawn in a diagram. Apropos to this article 

 is a second, by Messrs. Rand and Ulrich, on posterior 

 connections of the lateral vein in the skate. To the same 

 issue Mr. E. W. Berry contributes an article on fossil 

 sedges and grasses, with the description of a new Carex ; 

 and Mr. J. A. Cushman one on the fossil crabs from the 

 well known Miocene beds of Gay Head, Mass., described 

 long ago by Dr. E. Hitchcock, and subsequently by Sir C. 

 Lyell. 



An interesting paper on the gradual dissociation of 

 mellitic acid is contributed by A. Ouartaroli to the current 

 number of the Gazzetta Chitnica Italiana, vol. xx.w. p. 470. 

 The author has measured the rate at which cane sugar 

 is inverted by mellitic acid and by the corresponding 

 mono-, di-, tri-, tetra-, and penta-sodium salts in one- 

 tenth molecular solution. If the velocity constant for the 

 free acid is represented by 100, the values for the various 

 salts in the order given are respectively 40-5, 14-3, 22, 

 15, and 1-04. These numbers may be taken as a measure 

 of the relative tendencies to ionisation of the six successive 

 acid hydrogen atoms. Taking the ratio of the first to the 

 second, of the second to the third, &c., the series 247, 

 282, 649, 1-47, 143 is obtained. These numbers are 

 interesting, and the occurrence of a maximum value in the 

 middle of the series suggests that the dissociation of 

 mellitic acid is of abnormal character. 



During the past week the Royal College of Surgeons of 

 Edinburgh has been celebrating its four hundredth anni- 

 versary. The college, which is the oldest medical or 

 surgical corporation in the United Kingdom, dates from 

 July I, 1505. The Royal College of Physicians of London, 

 the ne.xt in point of age, was officially established some 

 thirteen years later, i.e. in 15 18. The current number of 

 the Lancet contains an interesting account of the older 

 institution. 



The third number of the second volume of the Investi- 

 gations of the Departments of Psychology and Education 

 of the University of Colorado has reached us. 'Among 

 other contributions, those in which Prof. Francis Ramalcy 

 deals with the teaching of botany and zoology, and Prof. 

 Chas. A. Lory with the teaching of physics, are of special 

 interest. 



We have received a copy ot " Southern Rhodesia, 

 Information for Settlers," a small handbook issued by the 

 British South Africa Company. The title sufficiently 

 indicates the nature of the contents of the book, but it is 

 worth noting that many of the numerous illustrations are 

 of considerable geographical interest and value. 

 NO. 1865. VOL. 72] 



The report of the Royal Cornwall Polytechnic Society 

 for 1904 has just been published, and bears testimony to 

 the continued vitality of the society. One of the chief 

 features of the society's activities during the year was its 

 exhibition, in connection with which addresses and papers 

 were given on electrical research, practical bee-keeping 

 and management, and the geology, minerals and mines 

 of Lelant, St. Ives, and Zennor. The first and last of 

 these communications are to be found in the report before 

 us, as is also an informing paper by Mr. C. C. Bignell 

 on the aphides with their food plants ; the volume like- 

 wise contains a detailed report of the work accomplished 

 at the Falmouth Observatory. 



The new number of the Quarterly Review contains only 

 two papers dealing with scientific subjects, one on the 

 national coal-supply, the other, by Sir Charles N. Eliot, 

 on the Buddhism of Tibet. Both communications are 

 very informative and eminently readable. 



Messrs. R. and J. Beck, Ltd., of Cornhill, have just 

 issued a catalogue of microscopes and apparatus specially 

 suited for metallurgical work. 



OUR ASTRONOMICAL COLUMN. 



Astronomical Occurrences in August: — 

 Aug. 2. ih. Mercury at greatest elongation (27° iS' E.). 

 ,, 2. I2h. 2Sm. to I4h. 6m. Transit of Jupiter's Sat. III. 

 (Ganymede). 

 4. Pallas in opposition to the sun. 

 11-13. Epoch of Perseid meteotic shower (Radiant 



45° + 57°)- 

 12. Saturn. Major axis of ring =43"'82, Minor axis 



= 7"'47- 

 14. loh. Venus in conjunction with Neptune, Venus 



o" 48' S. 

 14. Partial eclipse of the moon visible at Greenwich. 

 I4h. 39m. First contact with shadow. 

 I5h. 41m. Middle of the eclipse. 

 i6h. 43m. Last contact with shadow. 

 Magnitude of eclipse =o'292. Moon sets l6h. 53m. 

 ,, 15. gh. Saturn in conjunction with moon, Saturn 



ih. 43m. S. 

 ,, 15. Venus. Illuminated portion of disc =o'6So, of 



Mars =0'S54.' 

 ,, 16. Iih. 49m. Minimum of Algol {8 Persei). 

 „ ig. Sh. 3Sm. Minimum of Algol (;8 Persei). 

 ,. 22. 2ih. cm. Saturn in opposition to the sun. 

 ,, 23, I2h. 5m. to 12h. ■46m. Moon occults a- Tauri 



(Mag. 4-8). 

 ,, 30, Total eclipse of the sun, partly visible at Greenwich, 

 iih. 4gm. a.m. Beginning of the eclipse, 

 ih. 3m. p.m. Middle of the eclipse. 

 2h. 15m. p.m. End of the ecli|>se. 

 Magnitude of eclipse = 0786. Sun's altitude at noon =48°. 



Photographs of the Martun Canals. — Since the 

 opposition of Mars in 1901, persistent efforts have been 

 made at the Lowell Observatory to secure photographs of 

 the planet on which the canals could be seen definitely. 

 After making a number of exposures with a camera in 

 which the film was continuous, so that a large number of 

 short exposures — as in the bioscope — could be made on 

 the one film, Mr. Lampland succeeded in obtaining 

 negatives which demonstrate indubitably the actual exist- 

 ence of the " canals " Nilosyrtis, Pyramus, Casius, 

 Protonilus, Astaboras S., and Thoth. In addition to these, 

 the " regions " .Syrtis Major, Mare Erythra;um, Mare 

 Icarium, Hellas and the north polar cap, and the " oasis " 

 Lucus Ismenius are plainly discernible. A photographic 

 print from a negative secured on May 11 at igh. 44m.- 

 48m. (G.M.T.) on which these features are visible is 

 affixed in the I.ou^ell Observatory Bulletin, No. 21, accom- 

 panied by a drawing made by Mr. Lowell immediately 

 before the exposure was made. Other photographs secured 



