April 1 6, 1896] 



NATURE 



565 



We have received the meteorological Jahrbuch of the obser- 

 vatory of the Magdeburg Journal for the year 1894. The 

 resuhs are given in the same form as in the previous twelve 

 volumes, and the work is a good sample of the way in which 

 complete observations and means may be condensed into a com- 

 pact and convenient form. The first part contains eye observa- 

 tions made thrice daily, and the second part contains hourly 

 observations from self-recording instruments with facsimile traces 

 of the sunshine recorder, and also curves of the barograph and 

 thermograph for periods of disturbance, mostly during thunder- 

 storms. The highest shade temperature recorded during the 

 year was 94° "3 in July, and the lowest o^-g, in January. The 

 total annual rainfall amounted only to 19*4 inches, and the 

 greatest fall in twenty-four hours was i '6 inches. 



Among the papers published in the March number of the 

 foiirnal of the Royal Horticultural Society (vol. xix. part 3, 

 1896), are three to which attention may profitably be directed 

 here. Mr. Francis Darwin has a paper on " Etiolation as a 

 Phenomenon of Adaptation." Mr. A. W. Sutton contributes 

 ui account of the introduction ..and cultivation of the potato, 

 illustrated by numerous figures. lie has made some grafting 

 experiments with the potato and tomato, and describes his 

 results in his paper. As a result of introducing a tomato graft 

 upon a potato stem, the potato roots, maintained in growth by 

 tomato foliage, produced a crop of potatoes in the pot, while the 

 tomato foliage above ground produced a crop of tomatoes, 

 nourished by the potato roots in the pot. In a short paper. 

 Dr. Maxwell Masters describes a number of substitutes for larch. 

 He shows that there are many conifers which more or less fully 

 realise the characteristics of an ideal substitute for larch trees. 



When Henri St. Claire Deville, in company with Debray, 

 Morin, and Rousseau Bros., erected the first plant specially 

 designed for the manufacture of aluminium, forty years ago, 

 they did not foresee the greatness of the future of the industry 

 they founded. A sign of the growth of the industry in the 

 United Kingdom is the appearance of a monthly periodical, 

 Altiminiutn and Electrolysis, which will be concerned with all 

 matters pertaining to the manufacture and use of the metal. 

 France and the United States have for some time led the way 

 in aluminium manufacture, and have had their special journals, 

 but no paper primarily devoted to the interests of aluminium 

 has hitherto been published in the United Kingdom. The 

 addition to the ranks of industrial journals is made at an 

 opportune time, for, after a period of quiet, once more 

 increased attention is being given to aluminium in Great 

 Britain. 



It is not given to many scientific discoveries to command so 

 much popular attention as Rontgen's discovery of the X-rays ; 

 and the demand for information on the subject has resulted in a 

 copious supply of lectures and literature, while the desire to 

 revel in the marvellous has been gratified by a plenitude of 

 photographs of invisible objects, published in various forms. 

 Messrs. Valentine and Sons have added to their series of 

 collotype view-books a brochure containing reproductions of 

 eight Rontgen photographs taken by Profs. E. Waymouth Reid 

 and J. P. Kuenen at University College, Dundee. A brief 

 description is given of the method of work, and of each photo- 

 graph. Another publication on the same subject, by August 

 Dittmar, has been published by Mr. F. Bauermeister, Cilasgow. 

 This pamphlet contains a general statement of th? elementary 

 principles which result in the production of kathode rays and 

 Rontgen photography, illustrated with eleven text-figures and 

 one photograph obtained by means of X-iays. 



Amongst the products of the reaction at 400°- 500" of 

 hydrobromic acid upon phospboryl trichloride, M. Besson 

 NO. I 38 I, VOL. 53] 



(Coinptes rendits, April 11) has succeeded in isolating the 

 missing phosphoryl chlorobromide POClBrj. This is a solid 

 substance at the ordinary temperature, melting at 30°, and 

 distilling under normal atmospheric pressure at 165°. Its 

 boiling-point is not fixed, hosvever, as it slowly decomposes 

 into the chlorobromide POCljBr of Menschutkin and phosphoryl 

 tribromide, a property which renders its isolation by fractional 

 distillation difticult. Besides these two chlorobromides and the 

 tribromide, M. Besson obtained considerable quantities of solid 

 phosphorus pentabromide from the product of the original re- 

 action. The formation of this substance is remarkable, as it 

 involves the replacement of the oxygen of the phosphoryl group 

 by bromine with elimination of water, whereas at ordinary tem- 

 peratures the inverse change is known to take place with great 

 vigour. / 



The additions to the Zoological Society's Gardens during the 

 past week include a Rhesus Monkey (Macactts rhesus, i ) from 

 India, presented by Mr. Owen L. Hancock ; a Red and Blue 

 Macaw (Ara macad) from Central .\merica, presented by Mr- 

 Eugene E. G. Jones ; a Dusky Duck (Anas obsdtra, 9 ) from 

 North America, presented by Mr. W. H. St. Quintin ; an Indian 

 Elephant [Elephas indiciis, <J ) from India, two Red-beaked 

 Weaver Birds ( Qiielea sanguinirostris) from West Africa, a Java 

 Sparrow [Padda oryzivora) from Java, a Rose-breasted Grosbeak 

 {Hedymeles ludovicianus) from North America, a Lesser Black- 

 backed Gull [Larits ftisctis), British, deposited ; a Caffer Cat 

 {Felts caffra) from South Africa, purchased. 



OUR ASTRONOMICAL COLUMN. 

 MiRA Ceti. — For some years past it has been found that the 

 predicted maxima of this famous variable star, based upon a 

 period of 331 days, have been several weeks in advance of the 

 actual maxima, and it would seem that the time has arrived 

 when a new discussion of its light-curve should be undertaken. 

 According to the ephemeris, the last maximum was due on 

 December 9, but the greatest brightness did not occur until to- 

 wards the end of January, as shown by the following summary 

 of the observations (Btill. Soc. Ast. de France, April) : — 



-According to M. Dumenil (Coriiptes rendus, March 30), the 

 magnitude at maximum during the last twelve periods has varied 

 between 2-5 and 47. This fact, in conjunction with the apparent 

 irregularity of the light-curve, indicates that there is more than 

 one source of variability. On the meteoritic hypothesis the 

 variations are produced by two or more swarms of meteorites 

 revolving round a larger central swarm, and passing through its 

 outlying parts near periastron. On this supposition it may be 

 possible to analyse the light-curve of Mira.so as to determine the 

 part played by the individual sources of variation, each of which 

 may be perfectly regular. 



An Exhibition of Astronomical Photographs.— An 

 international exhibition of astronomical photography will form 

 part of the Berlin Industrial Exhibition to be held this year, 

 from May l to October 15. llerr F. S. Archenhold, who is 

 arranging the collection, has just sent out a circular asking for con- 

 tributions of photographs of astronomical instruments of historic 

 interest, of plans and buildings of observatories, as also the re- 

 productions of astronomical drawings and kindred subjects (such 

 as spectra, luminous night-clouds, ^:c.), lantern-slides 8i/lo cm. 

 in size, or larger, also separate heliogravures already published 

 in the annals of observatories, may be sent in to complete the 

 photographic collection. In all cases, where it is not especially 

 requested that they .shall be returned, photographs will be 

 retained and pre.served as a complete collection, which, together 



