July 26, 1877] 



NA TURB 



!55 



on the type of the silico-lungstic acids obtained by 

 Marignac. The new series of sails contain platinum 

 instead of silicon, and the salt ioW03Pt024Na,0 

 + 25 HjO has been obtained by boiling platinic hydrate 

 Pt(OH)j with acid rodic tungstate. Two metameric 

 sodium salts have been obtained, one of an olive-green 

 colour, the other honey yellow with an adamantine lustre. 

 The corresponding potassium and ammonium salts of 

 this platino-tungstic acid have also been obtained, but 

 they belong to the yellow series. Mr. Gibbs has not as 

 yet obtained salts corresponding to Marignac's twelve atom 

 silico-tungstates. Acid molybdate of sodium also dissolves 

 Pt(OH)j, giving a green solution, which appears red 

 when viewed in thick layers ; the only salt of this series 

 studied, crystallises in amber tabular plates having the 

 composition ioiM03PtO,4Na^O + 25H^O. He is endea- 

 vouring to generalise the results by substituting other 

 hydrates, such as Zn(0H)4, Ti(OH)„ Sn(OH)„ but has, 

 as yet, in these cases not obtained very definite results. 

 He is also engaged in examining the phospho-tungstic 

 acids containing 20WO3 obtained some time ago by 

 Scheibler. 



A SUPPOSED NEW Metal " Davium." — The discovery 

 of this new element is reported from St. Petersburg by 

 Serjius Kern. It was found by him in the residues of 

 platinum ores after treatment to separate out the metals 

 of the platinum group. The specific gravity of the metal 

 is given as 9'385 at 25°. The author supposes this new 

 metal to occupy an intermediate position between molyb- 

 denum and ruthenium, but very strong evidence will be 

 necessary to confirm the existence of a new metal belong- 

 ing to the platinum group. 



Effect of Pressure on Chemical Action. — M. 

 Berthelot, in a recent number of the Bull. Soc. Clwiii., 

 calls attention to the fact that some experiments lately 

 made by Quincke have confirmed a statement made by 

 the former chemist some time ago, that the evolution of 

 hydrogen from zinc and sulphuric acid is not arrested by 

 pressure. The experiments of Quincke show that when 

 these bodies are brought in contact, the pressure of the 

 hydrogen evolved rose in a few days from i'5 to 10 atmo- 

 spheres, and in a very much longer time from 25 to 126 

 atmospheres. Berthelot thinks that these experiments, 

 although not performed for this purpose, prove that 

 chemism is not modified, but only the nature and extent 

 of the surfaces attacked. The evolution of gas would 

 thus go on indefinitely, not arrested, but only modified in 

 rapidity. 



Amount of Oxygen contained in Sea-water at 

 DIFFERENT DEPTHS. — At a recent meeting of the Royal 

 Society of Edinburgh Mr. J. Y. Buchanan communicated 

 some results obtamed from his experiments on the above 

 subject during the cruise of the CliallcngLr. Mr. Buchanan 

 finds that at the surface the amount of oxygen varies 

 between 33 and 35 per cent., the higher numbers having 

 been observed in a water collected almost on the Antarctic 

 circle ; the smallest percentages have been observed in 

 thfe trade-wind districts. In bottom waters the absolute 

 amount is greatest in Antarctic regions, diminishing 

 generally towards the north. The oxygen percentage is 

 greatest over " diatomaccous oozes," and least over red 

 clays containing peroxide of manganese; over "blue 

 muds " it is greater than over " globigerina oozes." In 

 intermediate waters the remarkable fact was observed 

 that the oxygen diminishes down to a depth of 300 fathoms, 

 at which point it attains a minimum, after which the 

 amount increases. The following figures show the nature 

 of this phenomenon : — 



D Dth 1 1 i 1 I ' II tietween 80-3 



(lathoms) '1 °M ^° '°" °°° ' ^°° ''°° ^° boucm" 



(O + n'=i'5)o)} 33'7 I 33'4 j 32'3 | 30'2 33'4 | "'4 I5"S 22'6 | 23'5 



It is evident from these figures that between 20c and 400 



fathoms there is a great consumption of oxygen going on, 

 and, as it is difficult to conceive its being consumed 

 otherwise than by living creatures, the conclusion may 

 be drawn that animal life must be particularly abundant 

 and active at this depth, or at least more abundant than 

 at greater depths ; for, at less depths, there is more 

 opportunity of renewal of the oxygen by reason both of 

 the greater proximity to the surface and of the existence 

 of vegetable life. This conclusion is borne out by the 

 experiments of Mr. Murray with the tow-net at inter- 

 mediate depths, which go to prove the existence of 

 abundance of animal life down to 400 fathoms, vegetable 

 life never extending much below 100 fathoms. Below 

 400 fathoms life is sparingly met with. 



OUR ASTRONOMICAL COLUMN 

 The Total Solar Eclipse of 1605, October 12. — 

 It is known that Clavius attributed the ring of light which 

 he observed round the moon during the eclipse of April 

 9, 1 567, about the time of greatest obscuration at Rome, 

 to the circumstance of the sun's disc not being entirely 

 covered by our satellite, a narrow rim of light thereby 

 remaining visible. As Prof. Grant relates, in his 

 " History of Physical Astronomy," Kepler maintained 

 that the luminous ring seen by Clavius could not have 

 been the margin of the solar disc, because he found by 

 calculation that the moon was at her mean distance from 

 the earth, when her apparent diameter exceeds that of the 

 sun, even in perigee ; and when a similar ring of light was 

 remarked round the moon during the eclipse of February 

 25, 1598, and attributed to the same circumstance, Kepler 

 again pointed out that such an explanation was inadmissible, 

 themoon's apparentdiameter, on this occasion also, exceed- 

 ing that of the sun. These opinions were expressed by Kepler 

 in his work "Ad Vitellionem Paralipomena," published in 

 1604, and Prof. Grant remarks that an eclipse in the 

 following year strikingly confirmed them. This refers to 

 the eclipse of October 12, 1605, observed at Naples, of 

 which Kepler writes thus : {Uc Stella Nova in pede 

 Serpetitarii, p. 116) "the whole body of the sun was 

 effectually covered for a short time. The surface of the 

 moon appeared quite black, but around it there shone a 

 brilliant light of a reddish hue, and uniform breadth, 

 which occupied a considerable part of the heavens." We 

 follow Prof. Grant's translation of this passage, which 

 clearly proves that the eclipse was total for a brief interval 

 at Naples. 



As the eclipse of 1605 first confirmed the accuracy of 

 Kepler's views, in opposition to those of Tycho Brahd, 

 who disputed the possibility of a total eclipse of the sun, 

 it may not be without interest to examine the circum- 

 stances of the phenomenon as it would be observed at 

 Naples. For this purpose the same system of calculation 

 adopted for other eclipses mentioned in this column, is 

 followed. The elements are : — 

 G.M.T. of Conjunction in R.A. 1605, Oct. 12, at oh. 31m. 44s. 



197 1451-0 

 35 37-1 

 2 19T 

 6 40 27-9 S. 

 731 32-53. 

 10 50'2 S. 

 o 56-4 S. 

 5921-2 

 8-9 

 16 10-4 

 16 39 



The eclipse would therefore be central with the sun on 

 the meridian in long. 11° 18' \V. and lat. 52° 26' N., and 

 the following would also be points upon the central 

 line : — 

 Long. 19° 9' E., lat. 39° 32' ; and lorg. 14° 23' E., lat. 40° 48'. 



R.A 



Moon's hourly motion in R. A. 

 Sun's ,, ,, ,, 



Moon's declination ... 

 Sun's ,, 



Moon's hourly motion in decl. 

 Sun's ,, ,, ,) 

 Moon's horizontal parallax . . . 

 Sun's ,, ,, 

 Moon's true semi-diameter ... 

 Sun's ,, ,, 



