6o4 



NA TUBE 



[October i8, 1S94 



return until I have done everything that is possible for one who 

 believes in uhimate success, and whose every fibre is in sympathy 

 with and straining for the desired end." 



We are always glad to welcome any journal having for its 

 object the extension of scientific knowledge ; hence we note 

 with pleasure the publication ot' the first number of the Agri- 

 cultural J otirnal of the Lei7uard Islands, edited by Mr. C. A- 

 Barber, the Superintendent of Agriculture at St. John's, 

 Antigua, West Indies. The journal will ensure the rapid and 

 wide publication of the results of investigations of interest to 

 West Indian planters. It will be the medium through which 

 the work carried on in the Government laboratories, and in 

 experimental and botanical stations of the West Indies, will be 

 made public. But besides being the organ of the scientific 

 officers of the Government, the journal will contain reports of 

 the proceedings of the agricultural societies in the colony, and 

 facts of interest connected with the agriculture, natural history, 

 and meteorology of the different islands will be recorded. To 

 the number before us, the editor contributes some notes on the 

 nature of the irritating ticks from which the cattle of the West 

 Indies suffer. The j )urnal also includes an article on the 

 planting of eucalyptus trees ; one on hurricanes, by Mr. F. 

 Walts ; and a third, on coffee planting in the Leeward Islands. 

 The editor hopes to keep the journal scientific throughout, 

 although it must be made eminently practical. We hope and 

 believe that this addition to periodical literature will take a 

 permanent stand among the scientific journals of the tropics. 



The current number of the Cuot/>/«->v«</«j contains a paper 

 by M. R. Blondlot, on the propagation of electromagnetic 

 waves in ice, and on the specific inductive capacity of this 

 material. In a previous communication the author had shown 

 that for turpentine and castor-oil the wave-ltnijlh of the radia- 

 tion given out by an oscillator, in these substances, is the same 

 as in air ; and enunciated the general law that the wave-length 

 depends only on the dimension of the oscillator, and not on the 

 medium in which the oscillator is plunged. There was, how- 

 ever, considerable doubt whether this law would be found to 

 hold in the case of ice, for M. Bouly had found that the specific 

 inductive capacity of ice was 78, that is enormously greater 

 than in the case of any other dielectric. The apparatus 

 employed consisted of two copper wires stretched horizontally 

 and parallel at a distance apart of 80 cm. \ resonator made of 

 gilt copper, the same as that employed in the previous experi- 

 ments on liquids (Co/«//«-««</«j, July 25, 1892), was placed 

 between these wires ; the portion of the wires beyond the 

 resonator pass through a wooden trough four metres long. This 

 trough being empty, a bridge is moved along the wires beyond 

 the resonator till the sparks disappear, the distance between 

 the bridge and the resonator then being equal to the quarter 

 wavelength of the resonator. The resonator is then surrounded 

 with a water-tight bag filled with freshly-boiled distilled water, 

 which is then frozen. The quarter wave-length is now found 

 to be greater than before, in the ratio of 141 to 100 The 

 trough is then filled with water which is frozen, and by break- 

 ing away the ice the place at which the bridge has to be placed 

 in order to stop the sparking found. The wave-length under 

 these conditions i> exactly equal to that obtained when the 

 resonator and wire are surrounded by air. The experiment was 

 repeated four times, using resonators of different capacity, and 

 in every case gave the same result. The results obtained can 

 )>e utilised for calculating K the specific inductive capacity of 

 ice, and give for K the value 2, which value the author con- 

 sider* correct to within about ,'„. M. Blondlot having men- 

 tioned the above result to M. Perot, who, working by means of 

 electric oscillations, had found a very high value for K in the 

 case of ice, the latter examined his results, and found that he 



VO. 1303, VOL. 50I 



had made an error in the formula he employed. Having 

 applied this correction to his results, he now obtains the value 

 2 '04 for the specific inductive capacity of ice. 



A RECENT number of the Alii Jella Kealc Accadtmia dci 

 Lincei contains a paper, by M. .-Vscoli and V. Lori, on the radial 

 distribution of the induced magnetism in an iron cylinder. The 

 authors have investigated this question experimentally, using 

 cylinders of different lengths in magnetic lields of varying 

 strength. The cylinders employed were composed of 127 iron 

 wires, each of 0095 cm. in diameter. These wires were regu- 

 larly arranged round a central wire in layers containing 6, 12, 

 iS, 24, 30, and 36 wires respectively. Between each of the 

 layers was wound a coil of fifty turns of fine insulated copper 

 wire. By means of a series of mercury cups either of these 

 six coils could be connected to a ballistic galvanometer. The 

 authors find that for long cylinders (50 cm.) the distribution is 

 practically uniform, while in the case of shorter cylinders there 

 is an increase in the induction as you pass from the axis to the 

 circumference. This increase is particularly noticeable in the 

 case of short cylinders (5 to 10 cm.), and is greater in the case 

 of strong than of weak inducing fields. 



In theyiJU/Ma/ of the Scottish Meteorological Society (No. x. 

 third series), Dr. Buchan has published a very valuable 

 discussion of the mean monthly and .innual rainfall of Scotland 

 for the twenty-five years 1S66 to 1890. He points out that of all 

 the climatological elemtnls, rainfall calls for the greatest number 

 of years' observations in obtaining fairly approximate averages. 

 The period of twenty-five years now dealt with, for a large num- 

 ber of stations, and for the same years, may well be accepted as a 

 sound basis for discussion. In addition to the tables, and a 

 discussion of the principal features of each month, the depth of 

 rain for each month and for the year is shown on coloured ma^ s. 

 The part of Scotland where the rainfall is smallest is the low- 

 lying district round the Moray Kirth, where the annual amount 

 varies from 23 to 26 inches, the absolutely dryest place being 

 Nairn. Three parts of Scotland have an annual rainfall of 

 upwards of So inches, viz, the south-western half of Skye, the 

 highest mean annual lall being 92 inches, at Sligachan. To the 

 west of the Caledonian Canal, in the central parts of Ross- 

 shire and Inverness. shire and the north of .■Argyll, the average 

 at some stations exceeds 100 inches ; and to the south-east 

 of the canal the averages are still larger, amounting ta 

 over 127 inches in Glencoe. The work will be referiei 

 to as the standard authority on the rainfall of Scotland, 

 and when the publication of similar returns for the 

 United Kingdom, now bi;ing prepared by the Meteorological 

 Council, is complete, the distribution of the rainfall of these 

 islands will be fairly accurately determined. 



A f a recent meeting of the Berlin Physical Society, Herr K. 

 Pringsheim exhibited some examples of the application ol 

 phologiapliy to the deciphering of "palimpsest" ni.inuscripts. 

 A manuscript contained in the Royal Library at Berlin, on 

 which the process was tested, showed the s.cjnd writing 

 intensely black, while the older writing, washed oft as much as 

 possible to make way for the new, was larger, and showeil a 

 yellow tint. The pioblcm was to bring out in a pliotogr.Tph 

 the feeble yellow writing without the later black manuscript, 

 and this was accomplished as follows. .'V negative was first 

 oblaineil through a yellow screen, using a long exposure and a 

 flat development. This showed the older writing only very 

 feebly, and the later very well. Another negative was taken 

 with an ordinary bromide plate, was developed into a hard 

 image, and used to obtain a diapositive. This transparency 

 showed both writings with approximately equal intensity. The 

 transparency was then placed upon the first negative so tha 

 the two images coincided. In this case the background was 



