July 27, 1893] 



NATURE 



299 



once intelligible. It is that the new saginc shall be equal to the 

 double metre (o'9374of the present measure) and that a /fia// ia^i'«« 

 equal to one metre shall be divided into 20 vershoks (5 cm. are 

 equal to i '1248 of the present Virshok). Also that the new versta 

 shall be equal to the kilometre (0'9374 of the present versta), 

 the tmall desiaiina to the hectare and to 0'9IS3 of the present 

 desiatina ; the big cube to 10 cubic metres and to I '0296 cubic 

 sagcnes ; the small vedro to 10 litres and to nearly four-fifths 

 (0'oi3i) of the present i'^i//-o; \.he big measure {1000 litres) to 

 nearly five (4795) tehctveriks ; and finally the big pound (500 

 grammes) equal to i'22i Russian pounds. It will be seen that 

 the whole system is consistent with the spirit of the metric 

 system, which fully admits of measures obtained from the 

 multiplication of the metric ones by 2, 5, or 10, or from their 

 divisions by the same members. 



SiGNOR RiccARDO Arno has communicated to the Reale 

 Accademiadelle Scienze di Torino his results obtained during an 

 investigation of the diathermanous power of ebonite for heat 

 waves of various lengths. He employed six different sources of 

 light, whose radiant heat was sent through plates of ebonite of 

 thicknesses varying from 0'I2 to 052 mm. The thinnest of these 

 absorbed 25 per cent of the heat radiated from an incandescent 

 lamp, whose luminous heat rays were cut off by a thick plate of 

 glass. When the source of light was very bright, this film was found 

 to transmit a small portion of the visible red rays. Sixty-nine 

 per cent, of the dark rays from the smoked surface of a Leslie cube 

 containing boiling water were absorbed by the thinnest film, and 

 88 per cent, by the two others, thus showing that ebonite is less 

 transparent for dark heat rays of low refrangibility than for those 

 more approaching the visible spectrum. The greatest transpar- 

 ency was shown for the dark heat rays on the border of the 

 luminous spectrum. The successive substitution of a hot iron 

 plate, a glowing platinum wire, a Locatelli lamp, and an incan- 

 descent lamp for the Leslie cube brought about a steady 

 increase of transmitting power in all the specimens of ebonite. 



Profs. Bartoh and Stracciati have brought their eight 

 years' work on the specific heat of water to a close by reducing 

 the values obtained with the nitrogen thermometer as a standard 

 to the scale of the hydrogen thermometer. The corrected formula 

 for the quantity of heat necessary to raise the temperature of 

 I gramme of water from o" to t C, where t is less than + 31, as 

 given in the Rendiconti of the Reale Istituto Lombardo, is 

 I 006880/ - 278 X 10 «/- - 205 X 10 8^3 -t- 

 25375 X 10 "/^ - 26 X lo'^o/^ 

 This formula, obtained by eight different methods and several 

 thousand determinations, appears capable of serving as a reliable 

 basis for calorimetrical science. 



In afurthernotecontributedtothe Academy of Lincei, Augusto 

 Kighi continues the description of experiments he has conducted 

 with electrical oscillations of very small wave-length (see 

 Nature, June 22, 1893). The oscillator employed consists of 

 two small metal spheres surrounded with oil and held by two 

 rods of ebonite. These two spheres are placed between the dis- 

 charging rods of a large lioltz electrical machine. With 

 spheres 4 cm. in diameter the wave-length of the radiation ob- 

 tained was 20 cm., while with spheres of 1-3 cm. diameter 

 the wave-length was about 7 cm. The resonator employed 

 was of a novel form and was made by taking a rectangular 

 piece of ordinary silvered glass of such a size that its breadth 

 was equal to the length of the resonator required. The var- 

 nish was then dissolved off the back of the silver, and a line 

 drawn through the silver by means of a diamond, so as 

 T) divide the strip of silver into two equal parts, and form 

 I spark gap. By this means a spark gap was obtained, having 

 a breadth of between one and two thousandths of a millimetre. 

 For radiation having a wave-length of 7'5 cm. the resonator 

 NO. 1239, VOL. 48] 



was composed of a strip of silver 3 '9 cm. long and 0'2 cm. 

 broad. Although with these small wave-lengths the sparks 

 cease to be visible when the distance between the oscillator 

 and resonator is a metre, by placing a parabolic metallic 

 reflector behind the resonator the sparks were visible at a, 

 distance of six metres from the oscillator. Using the above 

 form of apparatus the author has repeated the experiments of 

 Lodge and Howard and others on the reflection and refraction 

 of electrical waves, he has also succeeded in producing inter- 

 ference between the rays reflected from two mirrors inclined at 

 a slight angle (Fresnel's experiment). An interesting set of 

 measurements of the transparency of various dielectrics gave 

 (amongst others) the following results : — Ebonite, paraffin, and 

 rock salt are perfectly transparent. A plate of mica i'7 mm. 

 thick absorbs 10% of the radiation, while a plate of ordinary 

 glass 8 mm. thick absorbs 37%, and a piece of quartz cut nor- 

 mally to the axis 8 mm. thick absorbs 40%. 



We have received the first part of " The Book of the Fair," 

 by Mr. Hubert Howe Bancroft. It is grandiloquently described 

 on the title-page as " An Historical and Descriptive Presenta- 

 tion of the World's Science, Art, and Industry, as viewed 

 through the Columbian Exposition at Chicago in 1893. 

 Designed to set forth the Display made by the Congress of 

 Nations, of Human Achievement in Material Form, so as the 

 more effectually to illustrate the Progress of Mankind in all the 

 Departments of Civilised Life." The part of the book before 

 us deals with great fairs of the past, and the history of Chicago, 

 the object apparently being to make the story as long as possible. 

 Both the text and illustrations are excellent. 



A COLLECTION of meteorological tables, compiled by Dr. 

 Arnold Guyot, was issued by the Smithsonian Institution in 

 1852. The fourth edition was published in 1884, and the work 

 had then grown to a bulky tome of more than 700 pages. 

 Upon a demand for a fifth edition, Prof. S. P. Langley decided 

 to publish the tables in three parts : Meteorological Tables, 

 Geographical Tables, and Physical Tables, each independent 

 of the other, but the three forming a homogeneous series. The 

 volume of meteorological tables is before us, and it is of far 

 more handy dimensions than formerly. Everything appertain- 

 ing to meteorological work appears to be contained therein, 

 and the fact that the work comes from the Smithsonian Insti- 

 tution vouches for its excellence. Our attention has been 

 directed to a slip on p. 248. In the list of meteorological 

 stations in the British Isles given on that page we find printed 

 "Richmond {Greenwich Observatory)," \aX. 5i°29'N., long. 

 0° o'. The first word should be omitted in future editions, for 

 Greenwich, and not Richmond, is obviously referred to. 



Nineteen charts of the " Isle of Wight and Solent Tides," 

 from Portland Bill to the Owers, have been prepared by Mr. 

 T. B. C. West and Mr. F. Howard Collins, and are published 

 by Mr. J. D. Potter, Poultry, E.G. They show by means of 

 arrows the direction of tidal streams at all hours, and, at some 

 places, for half hours of the tides. The rates given are for 

 spring tides, but those for neap and average tides can easily be 

 estimated. The charts are excellently engraved from an Ad- 

 miralty chart, and the arrows are placed in accordance with the 

 information contained in the " Channel Pilot. " They are issued 

 in an extremely compact form, and to the yachtsman of the 

 Isle of Wight district must prove invaluable. 



" Evolution and Religion," by Mr. A. J. Dadson, has 

 been published by Messrs. Swan, Sonnenschein and Co. The 

 first three chapters of the book are concerned with the doctrine 

 of evolution, and the remainder deal with theological matters, 

 while the whole has been written with the laudable object of 

 bringing about a reconciliation between religion and science. 

 ' May the truth prevail. 



