June 28, 1906] 



NA TURE 



209 



practical advice on the treatment of trees to produce early 

 ripr-nlng of the fruit, recommending root pruning and timely 

 clearance of all fruit at the end of the season. 



TiiK regulations governing the training of probationers at 

 Oxford for the Imperial staff of the Indian Forest Service 

 naturally arouse keen interest in India, and an editorial 

 article in the Indian Forester (April) compares the course 

 of studies prescribed at Oxford with the course given to 

 recruits for the subordinate executive service at the Imperial 

 Forest School, Dehra Dun. The opinion is expressed that 

 the course at Oxford requires stiffening, and the immense 

 advantage of obtaining practical experience at Dehra Dun 

 under Indian forestry conditions as contrasted with those 

 in European forests is emphasised. An article on felling 

 timber in Bashahr, contributed by Mr. G. S. Hart, in which 

 the felling of trees uphill is advocated, is accompanied by 

 some interesting photographs. 



In the Naturwissenschaftliche Wochcnschrift (June 17) 

 there is an excellent summary of what is known respecting 

 the structure of the reproductive cells, illustrated with a 

 niuiiber of particularly good figures. The author is Dr. C. 

 Thesing. 



The Bulletin of the Johns Hopkins Hospital for June 

 (xvii., Xo. 183) contains articles on the use of quinine 

 during the Civil War, by Dr. J. W. Churchman ; on an 

 experimental study on the regeneration of lymphatic vessels, 

 by Dr. .-V. W. Meyer ; and various medical papers. 



The Livingstone College " Year-book " for the current 

 year contains the annual report, extracts from letters of 

 former .students, &c. The college is doing a useful work 

 in giving to those about to become missionaries elementary 

 training in medicine, surgery, and hygiene. 



The New Jersey State Legislature has recently passed 

 an .Act for the extermination of mosquitoes. The title of 

 the .Act is as follows : — " An .Act to provide for locating 

 and abolishing mosquito-breeding salt-marsh areas within 

 the State, for assistance in dealing with certain inland 

 breeding places, and appropriating money to carry its pro- 

 visions into effect." The full text is given in Science 

 (June i). 



The preservation of brains for anatomical and anthropo- 

 logical investigations is the subject of an elaborate paper 

 by Mr. .Ales Hrdlicka (Proc. U.S. National Museum, xxx., 

 p. 245). It is found that the best preservative is a mixture 

 of formalin, water, and 95 per cent, alcohol in varying 

 proportions according to size : formalin 3 parts, distilled 

 water 45-25 parts, alcohol 52-75 parts ; less water and 

 more alcohol being used for the larger sized brains. 



The Local Government Board has published a further 

 report on the destruction of rats and disinfection on ship- 

 board with sulphur dioxide, by Dr. John Wade (No. 232). 

 It is found that rats and insects are destroyed in less than 

 two hours by air containing 05 per cent, of sulphur 

 dioxide, a condition easily realised in cabins, emptv holds, 

 spaces round cargo, S;c., but for adequate penetration of 

 closely packed cargo, air containing 3 per cent, of the gas 

 must be circulated around the cargo for eight to twelve 

 hours. Non-sporing pathogenic bacteria are also killed by 

 this treatment. Textile fibres and fabrics, metal and furni- 

 ture, are not affected by sulphur dioxide, but are liable to 

 injury by the accompanying sulphuric acid when the gas 

 is generated by burning sulphur, unless they are protected. 

 Meat, fruit, vegetables, and wheat in bags are deleteriously 

 affected. Liquid sulphur dioxide may be employed as a 



NO. 1913, VOL. 74] 



source of the gas, but burning sulphur, as in the Claylotj 

 process, is on the whole preferable on the ground both of 

 convenience and of economy. 



In the Engineering Magazine (vol. xxxi.. No. 3) Mr. 

 J. A. Macdonald gives an interesting account of twelve 

 months' prospecting and surveying in northern Ontario, 

 and also a detailed account of the occurrence of cobalt 

 ore and of the development of the deposits. These de- 

 posits, which contain silver, cobalt, nickel, and arsenic, 

 are among the most remarkable now engaging the atten- 

 tion of the mining world. 



We have received from the director. Prof. G. Gerland, 

 a circular summarising the work of the Central Bureau at 

 Strassburg of the International Seismological Association. 

 The bureau was founded in 1903 by the second Inter- 

 national Conference of Seismology. The observatory or 

 central station in connection with the bureau is furnished 

 with a triple horizontal pendulum with photographic 

 registration, a Rebeur pendulum for recording photo- 

 graphically two components, a Milne pendulum, a 

 Wiechert pendulum, a Vicentini microseismograph, Omori 

 and Bosch horizontal pendulums, and a trifilar gravimeter. 

 The apparatus and records are always at the service of 

 foreign observers. The bureau and the station have dis- 

 tinct organisations, but work together. The director hopes 

 that seismologists in other countries will transmit regularly 

 to the central bureau accurate observations of any seismo- 

 logical disturbances in their respective districts. The most 

 practical way. Prof. Gerland suggests, would be for 

 observers at the various stations to send copies of important 

 earthquake records to the bureau at Strassburg, where 

 they would be available for inspection by students of 

 seismology. 



With the advance of refractometry in chemistry, Messrs. 

 Carl Zeiss, of Jena, have introduced several forms of re- 

 fractometers suitable for special purposes, and have issued 

 pamphlets descriptive of these. Their " dipping refracto- 

 meter " is specially applicable in analysis, particularly in 

 ascertaining the proportion of alcohol and extract in beer. 

 For scientific purposes it gives very accurate values between 

 the ranges of /ii, = i-325 and 1-366, and is especially adapted 

 for the examination of aqueous solutions. The firm has 

 issued in pamphlet form a bibliography of papers dealing 

 with their well-known Abbe refractometer, and the refracto- 

 meters used in examining milk and butter respectively. 



In continuing their studies in luminescence, Messrs. 

 E. L. Nichols and Ernest Merritt in No. 5 of the Physical 

 Review investigate the law of decay of the phosphorescence 

 of Sidot blende. In previous experiments in this connec- 

 tion the decay of the total light has been measured, the 

 assumption being made that all portions of the light decay 

 at the same rate. In the present investigation the decay 

 of light of a definite wave-length in the phosphorescence 

 spectrum has been observed, and it is shown that in such 

 a case the intensity of the light diminishes according to the 

 law originally proposed by H. Becquerel, \-i = a+bt, where 

 a and b are constants. This law can be deduced from 

 different theoretical conceptions from those originally sug- 

 gested by Becquerel. It is only necessary to apply Wiede- 

 mann's hypothesis of the cause of photoluminescence and 

 to assume a law of recombination of the dissociated parts 

 of the substance similar to that which has been applied 

 to the case of ionisation of gases. With such an assump- 

 tion it is deduced that the quotient alb should be the same 

 for different wave-length; when the excitation and other 



