February 15, 1094 J 



NATURE 



371 



which the positive picture is printed. The negative is saturated 

 with kerosene for the purpose of clarifying. 



Mr. G. Nicholson, the curator of the Royal Gardens, 

 Kew, contributes to the February number of the tCe^v Bulletin 

 a report on horticulture and arboriculture in the United States. 

 It contains accounts, among others, of visits to the following 

 gardens : — Holm Lea, near Brooklime, Mass., the residence of 

 Prof. C. S. Sargent ; the Arnold Arboretum, of Harvard 

 University, at Jamaica Plain, Mass. ; th2 Missouri Botanical 

 Garden at St. Louis ; the Horticultural Exhibition at Chicago ; 

 the Mount Hope Nurseries at Rochester, N,"S'. ; and Meehan's 

 Nursery, Germantown, Philadelphia. The paper also contains 

 notes on railway gardening, and on the native flora of the 

 districts passed through. 



An interesting paper on the possible transmission of the 

 tubercle bacillus by cigars, has appeared in the current number 

 of the Centralblatt jitr Bakteriologie. Dr. Kerez, in the pre- 

 face to his experiments, points out that ample opportunity is 

 given for the infection of cigars with tuberculous material, as so 

 caany of the people employed in tobacco manufactories are 

 known to suffer from consumption. The manner in which the 

 cigars may become infected is apparent when it is remembered 

 that by force of habit and convenience the tobacco-workers 

 prefer to use their saliva for getting the leaves to adhere in 

 cigar making, instead of the materials supplied to them for this 

 purpose. In this way the tubercle bacillus is easily conveyed 

 to the cigar. Dr. Kerez has, therefore, imitated in every detail 

 on a small scale the manufacture of cigars, using saliva con- 

 taining tubercle bacilli for the moistening of the leaves. After 

 being dried and packed away in boxes, cigars preserved for 

 different lengths of tima were carefully unrolled, the leaves 

 washed with water, and the infusion inoculated into guinea-pigs. 

 In all cases where the infected cigars had only been kept for ten 

 days, the animals treated with the tobacco infusion died of 

 tuberculosis, but when the cigars were kept for longer periods 

 the animals suffered no ill-effects, indicating that during this 

 time the tubercle bacilli had either been destroyed or deprived 

 of their virulent character. As long, therefore, remarks Dr. 

 Kerez, as the cigars, presuming them to have been infected in 

 the course of making, are kept for a sufficiently long time in 

 the manufacturer's hands before distribution, this possibility of 

 spreading consumption may be ignored. 



A CATALOGUE (No, vi.) of works on geology offered for 

 sale by Messrs. Dulaif and Co. has just been issued. 



A CHEAP edition of "The Religion of Science," by Dr 

 Paul Carus, has been published by the Open Court Publishing. 

 Company, Chicago. 



Messrs. Horne and TnoRNTHWAixEhave published anew 

 descriptive catalogue of astronomical telescopes and other optical 

 instruments. 



A second edition has been published of the catalogue of the 

 Camera Club Photographic Library, compiled by Messrs. L. 

 Clark and W. Brooks. 



Messrs. Blackie and Son have published a guide to the 

 examinations in elementary agriculture of the Department of 

 Science and Art, and answers to the questions set in the subject 

 from 18S4 to 1893. 



"A Short History of Astronomy," compiled by Mr. 

 George Knight, and published by Messrs. G. Philip and Son, 

 is a little book of twenty-seven pages, in paper covers, con- 

 taining a sketch of the growth of astronomy suitable to begin- 

 ners, and likely to create a desire for fuller knowledge. 



The first edition of Mr. Bo wen Cooke's work on "British 

 Locomotives " being nearly exhausted, the publishers announce a 



NO. 1268, VOL. 49] 



second and revised edition as almost ready for issue. The same 

 publishers (Whittaker and Co.) announce a work on " Survey- 

 ing and Surveying Instruments," by Mr. G. A. T. Middleton. 



We announced towards the end of last year that the Bntish 

 Nahiralist would be discontinued after the December number. 

 General regret having been expressed at the proposed discon- 

 tinuance of that useful magazine, the opinions of some well- 

 known naturalists were obtained, and with the result that 

 arrangements were eventually made for carrying on the publica- 

 tion. The first number of the new series is before us, and its 

 contents will be appreciated by the student of natural history 

 and collector. Edited by Messrs. J. Smith and L Greening, 

 and with the assistance of the late editor, Mr. J. E. Robson, 

 and others, the magazine should have a wide circulation among 

 naturalists in all parts of the country. 



Messrs. Macmillan and Co. will publish immediately a 

 volume of "Essays in Historical Chemistry," by Prof. Thorpe, 

 based on lectures and addresses delivered during the last twenty 

 years. The list of subjects includes Boyle, Priestley, Scheele, 

 Cavendish, Lavoisier, Faraday, Thomas Graham, Wohler, 

 Dumas, Kopp, and Mendeleef. 



Mr. Henry' Louis has prepared, and Messrs. Macmillan 

 and Co. are about to publish, a " Handbook of Gold-Milling," 

 I in which the subject is treated for the first time in a form at 

 I once scientific and practical. It is hoped that the book may be 

 found useful not only for the technical instruction of mill-men, 

 j but also for the guidance of managers and managing directors of 

 : gold-mines. The work begins with an account of the physical 

 1 and chemical properties of gold, and also of mercury; stamp- 

 . mill construction is considered in detail, the mechanical prin- 

 ciples underlying the design of each part being throughout 

 i elucidated. The theory and practice of concentration, as far 

 as it refers to gold-milling, is next considered, together with 

 the most approved modern method of treating the concentrates 

 and other products of milling. Chapters are appended on the 

 e conomic considerations involved and on the assaying of gold 

 ores and products. The book is fully illustrated. 



Two new boron compounds, diphenyl boric acid ani the cor- 

 responding chloride, have been obtained in the Rostock Labora- 

 tory by Prof. Michaelis, and an account of them, together with 

 several other more complex aromatic derivatives of boron, is 

 contributed to the latest issue of the BcHchte. In the year 

 1879 Prof. Michaelis, in conjunction with Dr. Becker, succeeded 

 in preparing phenyl boron chloride, C^HsBCL, the first boron 

 compound containing a benzene radicle. This interesting sub- 

 stance, a liquid which boils at 175°, was obtained by heating 

 together to about 200' in a sealed tube the corresponding 

 quantities of boron chloride, BCI3, and mercury diphenyl, 

 Hg(C^H,5)._,. Upon bringing it in contact with water a beauti- 

 fully crystalline and powerfully antiseptic substance, pheny 

 boric acid CeH5B(OH)._,, was produced, which upon heating 

 evolved water vapour, and yielded the anh>dride CgHjBO. It 

 is now shown that diphenyl boron chloride, (CgHjliBCl, is 

 formed when the mono-phenyl compound is heated along with a 

 further quantity of mercury diphenyl to 300-320° in a sealed 

 tube. The product is a mixture of diphenyl boron chloride 

 with mercury chloro-phenyl Hg(C,;H.,)Cl, from which latter 

 compound the former may be separated by extraction with an 

 organic solvent. Upon distillation of the extract a liquid is 

 eventually isolated which boils at 270°, and which proves to be 

 pure diphenyl boron chloride. It is a thick colourless liquid 

 which fumes slightly in moist air. Upon heating with water it 

 is decomposed with formation of a substance endowed with an 

 exceedingly powerful and penetrating odour. This substance 

 rapidly collects as an oil upon the surface of the water. After 



