January 27, 1898] 



NATURE 



303 



An amusing instance of the want of observation of the 

 commonest phenomena of nature has come under our notice in 

 a schedule of the " Language of Flowers " issued by a well- 

 known firm of perfumers. The symbol for "assiduous to 

 please" is "sprig of ivy with tendrils" ! 



Dr. a. Wagner, of Neuhaus am Inn, Bavaria, issues a list 

 of fifty microphotographs at i m. and i m. 50 each, a re- 

 duction on a quantity. The subjects are entirely botanical, and 

 include sections and microscopic organs of Phanerogams and 

 Cryptogams. 



During February the following science lectures will be given 

 at the Royal Victoria Hall : — February I, " Insects in a London 

 Back Garden," Mr. F. Enoch. February 8, " The Problem of 

 the Great African Lakes," Mr. J. E. S. Moore. February 15, 

 "Brains," Mr. Hugh de Haviland. 



Mr. S. B. J. Skertchly has a note, in the "Geological 

 Survey of Queensland," on a plant which he calls the "copper 

 plant," Polycarpcea spirostyles, belonging to the Caryophyllacete. 

 He finds it always associated with copper lodes, and thinks it 

 may be of use, on this account, from a practical point of view. 

 Analysis shows the ash to contain an appreciable amount of 

 copper. 



Dr. C. E. Bessey republishes, in a separate form, his 

 address as retiring president of the Botanical Society of America, 

 entitled " The Phylogeny and Taxonomy of Angiosperms." A 

 modification, to a not very large extent, is proposed of the 

 systems of De Candolle and of Eichler and Prantl, by which it 

 Ls thought that the phylogenetic relationships of the orders of 

 Monocotyledons and Dicotyledons are more completely indicated. 



We have received the first three numbers of a new 

 serial, the Circular of the Royal Botanic Gardens, Ceylon, in- 

 tended to deal with agricultural, horticultural, and botanical 

 topics, with special reference to the work carried on in 

 the Botanic Garden. The chief subject treated in these 

 numbers is the canker of the cacao tree, its cause, and the pos- 

 sible remedies, including a correspondence on the subject with 

 the authorities at Kew. 



Mr. J. H. Hart, the Superintendent of the Royal Botanic 

 Garden, Trinidad, has commenced, in the Bulletin of Mis- 

 cellaneous Information, the publication of a monograph of the 

 Ferns of the British West Indies and Guiana, prepared by Mr. 

 G. S. Jenman. Vol. iv. part 5 of the Bulletin, for January 

 1898, is entirely occupied by the two genera Hymenophyllum 

 and Trichomanes , twenty-nine species being described of the 

 former, and forty-two of the latter genus. 



A LEAFLET on " The Advantages of Boiling Drinking Water 

 and Milk " has just been published by the National Health 

 Society. It is written by Mrs. Percy Frankland, and is in- 

 tended for distribution amongst both rich and poor. It con- 

 tains a brief account of the dangers which may attend the use 

 of contaminated water and milk, and a few simple instructions 

 are given for ensuring the removal of any noxious germs which 

 may be present by the efficient boiling of these liquids. Copies 

 for distribution may be obtained of the Secretary of the Society, 

 53 Berners Street, London, W. 



The additions to the Zoological Society's Gardens during the 

 past week include a Mozambique Monkey {Cercopit heats 

 pygerythrus) from South-East Africa, presented by Miss 

 Refers ; a Smooth-headed Capuchin {Cebus monachus) from 

 South-east Brazil, presented by Mr. W. S. Jay; a Chinese 

 Goose {Anser cygnoides) from China, presented by the Rev. E. 

 Hensley ; a Beccaris Cassowary ( Casuarius beccarii) from New 

 Guinea, deposited. 



In the notice of Mr. Dodgson, the words " symbolically 

 developing and popularising " should be inserted before " the 

 Study" in the seventh line from the end (p. 280). 



NO. 1474. VOL. 57] 



OUR ASTRONOMICAL COLUMN. 

 Astronomical Occurrences in February : — 

 Feb. 3. i8h. 43m. to igh. lom. 5 Geminorum (mag. 37) 

 occulted by the moon. 



5. I7h. 34m. Near approach of o' Cancri to the moon. 



6. Pallas 1^ N. of t Eridani. 



9. loh. 13m. Minimum of 3 Persei (Algol), 

 II. 6h. Mercury I ' N. of Mars. 



11. I7h. 26m. to I7h. 54m. 89 Virginis (mag. 52) oc- 



culted by the moon. 



12. 7h. 2m. Minimum of /3 Persei (Algol). 



13- I9h. 33m. to 2oh. 37m. b Scorpii (mag. 4-8) occulted 



by the moon. 

 14. loh. 23m. Moon in conjunction with a Scorpii 



(An tares). 

 14. Illuminated portion of Venus = i '000. 

 ,, „ Mars = 0"98i. 



14. I7h. Saturn in conjunction with moon. Saturn 



5° 30' N. 



15. Venus i^" S. of the sun. 



23. 8h. 52m. to 9h. iim. Jupiter with only one visible 

 satellite. 



Theory of Periodic Comets. — We have already called 

 attention in this column (September 16, p. 473) to the recent 

 work of M. Callandreau on the subject of disaggregation of 

 cometary matter, and pointed out the lines he has followed in 

 his research. In the Annales de I'Observatoire de Paris, 

 Memoires, t. xxiii, , he has collected the results of his recent 

 work, and examined to what extent the theory is supported by 

 recent observations. The circumstances favourable for disrup- 

 tion are — close approach to Jupiter, small relative velocity, and 

 small excentricity of orbit. The question is, therefore, to what 

 extent do the elements of comets which have given evidence of 

 disintegration exhibit these peculiarities. It must be remem- 

 bered, that it is only since the comet of 1882 was seen to be 

 accompanied by faint nebulous matter that the neighbourhood 

 of a comet has been regularly explored to detect the presence of 

 companions. The most typical case yet noticed is that of the 

 comet of 1889 v., which was very numerously attended, and of 

 which it has been established that the orbit of at least one of 

 the companions cuts the orbit of the principal comet near its 

 aphelion. Since this comet, as Chandler has shown, made an 

 approach to Jupiter in 1886, it seems likely that the disruption 

 took place then, owing to the influence of that planet, since the 

 conditions indicated as favourable to the theory are all present 

 in this instance. The existence of the two distinct comets of 

 Wolf &.'.J Barnard (1892 V.) can with probability be traced to 

 the action of Jupiter, but the epoch at which the approach to 

 the planet occurred cannot be decided. 



The famous instance of Biela is inconclusive. A general in- 

 vestigation of the distance between the two nuclei shows that 

 this is greatest about perihelion, and least at, or near, aphelion. 

 The difficulty of identifying the two nuclei led Prot. Hubbard 

 to make two hypotheses in his calculations, and he preferred that 

 which gave the minimum distance between the two nuclei. But 

 M. Callandreau shows that adopting the second hypothesis, 

 which, though rejected by Hubbard, is by no means excluded 

 by the result of his researches, the division of the comet into 

 two parts would take place in Heliocentric Longitude 266^, while 

 the longitude of the point of closest approach of the orbit of 

 Jupiter and the comet is 268°. 



The suggestion that a family of comets with aphelia near the 

 orbit of Jupiter and with periods approximately half that of the 

 planet, should be introduced into the solar system by the action 

 of Jupiter, is not without its objections, based on the theory of 

 probabilities ; but the multiplication of comets by disruption is 

 free from this objection, and would also tend to explain the 

 faintness which is a feature of this class of comets. 



Photogr.\phic M.\gnitudes. — In Circular No. 22, issued 

 from the Harvard College Observatory by Prof. Pickering, the 

 question of photographic magnitudes of stars is considered. It 

 is pointed out that it is a matter of great importance to know 

 how much the relative brightness of star images will vary on 

 different plates, or on different portions of the same plate. It 

 is especially important to determine the amount of this error, 

 since it is not easily eliminated and has been supposed to be 

 large by some persons not familiar with stellar photographs. 

 A moment's investigation of photographs of the same portion 

 of the sky shows that this source of error is small, so small 



