1\1ay 7, 1908J 



NA TURE 



17 



a scale visible in the field of the instrument enables the 

 refractive index to be read directly to the second place of 

 decimals. The range extends from 1300 to 1775, which 

 includes the refractive indices of corundum (ruby and 

 sapphire), the only gem-stones falling beyond this being 

 almandine, demantoid, zircon, sphene, and diamond. The 

 two patterns of instrument have been described in detail 

 by Dr. Herbert Smith in the Mineralogical Magazine 

 (1905 and 1907), and a more popular account is given by 

 him in a pamphlet published by Mr. J. H. Steward (" The 

 Herbert Smith Refractometer, and its Use, particularly 

 for the Discrimination of Faceted Gem-stones," London, 

 1907, pp. 28). In this pamphlet a concise summary is 

 given of the methods applicable for the discrimination of 

 faceted gem-stones, it being pointed out that the determina- 

 tion of the refractive indices is often the only trustworthy 

 test that can be applied when the stones arc mounted. A 

 carefully compiled table of the constants of thirty-four 

 mineral species used in jewellery contains some new deter- 

 minations, and will be found useful for reference. 



The thirtieth yearly report of the Deutsche Seewarte, for 

 the vear 1907, shows that the work of that active and 

 useful institution has been continued on the same lines as 

 hitherto; the constant increase of its operations, as in the 

 case of most other meteorological organisations, has made 

 it necessary to add to its working staff. The number of 

 observers in the mercantile marine was 962 at the close 

 of the year ; they are encouraged in their work by the 

 award of medals and diplomas for excellent observations, 

 as well as by a liberal presentation of official publications. 

 The most important event of the year in the department 

 of weather prediction was the acquisition of telegraphic 

 reports from Iceland and the Fserbe Islands, which have 

 been found of great service ; the early morning reports 

 from the British Isles are also much appreciated. As in 

 this country, special forecasts for agriculturists are issued 

 during the summer season, but the dissemination of the 

 information is on a much larger scale. Exploration of the 

 upper air by means of kites and balloons is actively con- 

 tinued whenever practicable. 



In the monthly mereorological charts of the North 

 .Atlantic and Indian Oceans for May, issued by authority 

 of the Meteorological Committee, every available space is, 

 as usual, occupied with data of importance to seamen. 

 The face of the charts shows the average statistics relating 

 to the atmosphere and the sea for the month in question, 

 with latest intelligence on such subjects as ice, monsoons, 

 &c. Among the interesting matters dealt with on the 

 back of the charts we find a discussion of the observations 

 of the Sargasso or Gulfweed from the records kept for 

 the Meteorological Office during the seven years ended 

 1Q07, and the monthly frequency of fog in the Gulf of 

 St. Lawrence for the period 1892-1906. There are also 

 charts showing the cvclone tracks in the South Indian 

 Ocean for 1848-1905, and a picture of the Southern Ocean 

 ice during each of the months April to June, for twenty- 

 three years ended 1907 ; some of these huge icy masses 

 are said to have projected 1000 feet above the water-line, 

 and to have been from two to forty miles in length. 



Dr. Moschou, of Smyrna, has invented some improve- 

 ments in the beams and bearings for physical balances. 

 Balance beams have previously been designed which are 

 roughly elliptical in cross-section or are of a channel 

 section. According to the present invention, a section is 

 adopted which is approximately elliptical, but has vertical 

 sides, and if desired the elliptical tube may be strengthened 

 by a rhombic frame. The bearings of the balance liave 

 also been considerably modified; for the usual knife edges, 

 NO. 2010, VOL. 78I 



discs taking the form of two truncated cones placed base 

 to base are substituted. For the centre bearing there are 

 two such discs secured to the elliptical beam, and at the 

 ends of the beam similar discs are supported by small 

 axles. In some cases two discs are provided at each end 

 of the beam, and the balance pans are supported upon 

 these by hooks, hollowed at their bearing surfaces so that 

 they always take up the same position upon the discs 

 whenever they are removed and replaced. When two 

 discs are thus used, the swinging of the balance pans 

 backward and forward is largely prevented. 



P.ART V. of the Vcrhandlungen der deutschen physik- 

 alischcn Gesellschaft for the present year contains the 

 results of Dr. P. Nordmeyer's further .vork on the mean 

 specific heats of pure substances between the two tempera- 

 tures -188° C. and 18° C. The method is identical with 

 that used previously, and depends on the determination of 

 the weight of liquid air evaporated by a body at ordinary 

 temperature placed in it. The following are the values 

 obtained : — sodium, 0253 ; magnesium, 0-222 ; calcium, 

 0157; iron, 0097; molybdenum, 0-063; thallium, 0038; 

 gold, 0-033; aluminium, 0-182; yellow phosphorus, 0-178; 

 potassium, 0-170; bromide of potassium, 0103. 



.^N eighth edition of Mr. Andrew Jamieson's " Ele- 

 mentary Manual of Applied Mechanics " has been published 

 by Messrs. Charles Griffin and Co., Ltd. The book has 

 been revised, some additions have been made to the text, 

 and further examination papers included. 



Messrs. Smith, Elder and Co. have almost ready for 

 publication a work on " Animal Life," by Dr. F. W. 

 Gamble. The volume comprises a series of studies in the 

 life-history of typical members of the animal kingdom, 

 describing their vjtal activities in relation to their struc- 

 ture, and the general scheme of development. 



The current issue of the Central, the organ of the 

 Central Technical College Old Students' Association, con- 

 tains a .portrait of Dr. G. T. Moody, and articles on the 

 electrification of railways, by Mr. Lionel Calisch, and on 

 the City of Victoria and Hill district waterworks. Hong 

 Kong, by Mr. D. Jaff^. ' ; 



A THIRD edition of Dr. Alex. Findlay's translation of 

 Ostwald's " Principles of Inorganic Chemistry " has been 

 published by Messrs. Macmillan and Co., Ltd. The funda- 

 mental character of the book remains unaltered, and the 

 changes in detail are not great, but here and there slight 

 mistakes have been corrected and some additions made. 



The report of the council and proceedings of the Hamp- 

 stead Scientific Society for the year 1907 has been received. 

 The membership of the society now stands at 286, and its 

 finances are in a satisfactory state. As usual, the lectures 

 given at the general meetings during the winter have been 

 appreciated widely. .Among the list of lecturers we notice 

 the names of Prof. E. H. Starling, F.R.S., and of Dr. 

 C. \V. Andrews, F.R.S. The activity of the various 

 sections of the society has been well maintained. 



Mr. John Cooke, editor of Murray's " Guide to 

 Ireland," is preparing an account of the tumuli and other 

 pagan antiquities of the Boyne Valley for the " Hand- 

 book " of the British .Association. It is to be hoped that 

 at last their astronomical orientation will be given. Mr. 

 Nathaniel Colgan, author of the " Flora of Co. Dublin," 

 and one of the editors of " Cybele Hibernica," will deal 

 with the local botany. The geology of the immediate 

 neighbourhood of Duijlin is specially interesting, ranging 

 as it does from the Cambrian Bray Head to the Carbon- 

 iferous limestone of the great central plain. 



