DECEMliER 20, 1894] 



NATURE 



181 



This solution was then submitted to distillation at the tem- 

 perature of the water bath and under the reduced pressure of 

 68 m.m. of mercury. The distillate was received in two- 

 fractions, boiling at 7i°-8i' andSi°-85° respectively. The first 

 fraction contained 44 per cent. H,0,„ while the latter was 

 found to contain no less than 905 per cent. Upon again 

 fractionally distilling the latter product, a large proportion dis- 

 tilled at 84 '-85', and this fraction proved to be practically pure 

 HjOo, containing over 99 per cent, of the peroxide. The liquid 

 thus isolated is a colourless syrup which exhibits but little 

 inclination to wet the surface of the containing vessel. When 

 exposed to the air it evaporates. It produces a prickly sen- 

 sation when placed upon the skin, and causes the appearance 

 of while spots which take several hours to disappear again. As 

 regards the much-discussed and disputed question of the re- 

 action of hydrogen peroxide towards litmus, Dr. Wolffenstein 

 finds that even when the pure liquid is made strongly alkaline 

 with soda and again distilled, the distillate exhibits strong acid 

 characters, so that the acid nature of hydrogen peroxide must 

 be regarded as fully established. It is finally shown that the 

 use of ether in assisting the concentration is by no means 

 essential. Ordinary commercial 3 per cent, peroxide can be 

 immediately subjected to fractional distillation under reduced 

 pressure, and a fraction eventually isolated, consisting of the 

 pure substance boiling at 84'-85'' under a pressure of 68 m.m. 



The additions to the Zoological Society's Gardens during the 

 past week include a Common Fox {Canis vulpes), British, 

 presented by Mr. Harold von Lohr ; a Spotted Ichneumon 

 \HerpesUs nepaUnsis) from India, presented by the Misses 

 Violet and Sylvia Brockelbank ; two Curlews {Nitmenms 

 arquatd), British, purchased. 



OUR ASTRONOMICAL COLUMN. 



Secular Variations of the Interior Planets. — As 

 far back as 1859, Leverrier discovered that the movement of 

 the perihelion point of the orbit of Mercury was greater than 

 could be accounted for by the action of all the known planets, 

 and he attributed this to the effect of a group of unknown 

 bodies circulating between the orbit of Mercury and the sun. 

 Prof. Newcomb has recently gone over the ground again, and 

 the results of his work are given in Coinptes-rendtis of Decem- 

 ber 10. A brief statement of the tentative conclusions arrived 

 at was given in these columns on November 29 (p. 114). From 

 a discussion of a vast number of observations he has re- 

 determined the secular variations (or the orbits of Mer- 

 cury, Venus, the Earth, and Mar*, and he has computed 

 the masses of Mercury, V'enus, and Jupiter from the periodical 

 perturbations which ihey produce ; the adopted value of the 

 earth's mass is deduced from the parallax 8'''8o, and for Mars 

 the adopted mass is that derived from observations of the satel- 

 lites, it is then shown that with these masses the calculated 

 values of the secular variations differ from the observed ones, 

 the divergences being especially great in the movements of the 

 perihelia of the orbits of Mercury and Mars, and of the node 

 of Venus. Two explanations of the differences are open to us : 

 (l) It may be supposed, as suggested by Prof. Asaph Hall, that 

 the law of giaviiation.il attraction is not strictly true, and that 

 the attractive force of the sun varies inversely as the distance 

 raised to the power of approximately 2 000000 1574 ; (2) they 

 may be attributed to the influence of unknown masses of matter. 



At first sight, the second hypothesis seems preferable, as it 

 involves no departure from an accepted law, and because it is 

 the only one which will explain all the secular variations, while 

 on the first hypothesis the perihelia would alone be affected. If 

 there are unknown bodies between Mercury and the sun, Prof. 

 Newcomb shows that in order to produce the observed effects, 

 their mass must be great enough to produce a sensible 

 ellipticity in the sun's figure ; and as this has not been detected, 

 he prefers to place these unknown bodies between the orbits of 

 Mercury and Venus. He has computed the elements of an 

 orbit which would reduce all the discrepancies between observed 

 and calculated values of the secular variations to less than the 



probable errors, the mean tdistance being o'48, and the mass . 

 i/37,oco.oco h that of the sun. At the same time. Prof. 

 Newcomb re.ards this result more as a curiosity than as a 

 reality, as it seems improbable that such a group of bodies 

 should have escaped discovery. 



Returning to the other hypothesis, he finds that if we accept 

 Hall's modification of the law of gravitation, which accounts for 

 the movements of the perihelia, the variations of the other 

 elements can all be explained by slightly changing the value of 

 the earth's mass. The new value corresponds to a solar parallax 

 of 8"77. Although by no means regarding the latter hypothesis 

 as established, Prof. Newcomb is inclined to adopt it 

 provisionally. 



Irregularities in Variable Stars. — In a summary of 

 the observations of variable stars of long period, made by W. 

 Maxwell Reed at Harvard College Observatory and the Abbot 

 Academy {Astroit. Joiirn. No. 330), the importance of study- 

 ing the irregularities in the light curves is strongly insisted upon. 

 The observations indicate numerous "stand-stills,' or notches 

 in the light-curves, and these are believed to be secondary 

 phases produced by additions of light at those points. "A 

 record of over ten years for T Cephei gives ten more or less 

 well-defined stand-stills. The mean period is about twenty 

 days less than that of the variable (about 383 days)." From 

 studying these and other variables, Mr. Reed is inclined to 

 believe that " the light-curve, in some cases at least, is the sum 

 of two or more curves — each component curve having a different 

 range, period, and character from the others. By such a 

 hypothesis one can account for the changes in period and 

 range of a variable, and the presence of "stand-stills" and 

 secondary phases. Unfortunately, there is not enough evidence 

 yet to give the elements of the two or more component curves 

 for T Cephei." It will be remembered that Mr. Lockyer has 

 .also seen the necessity for supposing more than one source of 

 variation in many cases, and some of his examples of the peculiar 

 curves produced by integrating two perfectly regular ones were 

 given in our columns four years ago (Nature, vol. xlii. p. 550). 

 With Mr. Reed we regret that less attention has been given by 

 observers to the character of the light-curves of these variables, 

 than to the determination of the maxima and minima. 



The Radcliffe Catalogue.— The new star catalogue 

 recently issued by Mr. Stone contains the positions of 6424 

 stars (or the epoch 1S90, deduced from observations made with 

 the transit circle at the Radcliffe Observatory between January 

 I, 1S81, and December 31, 1893. Up to 18S7 a considerable 

 number of observations were made for the determination of 

 systematic errors o( the instrument and for errors of the 

 refraction tables. Since then the observations have been more 

 exclusively directed to obtaining the positions of stars for well- 

 distributed zero-points between the equator and N. P.O. 115', 

 in continuation and completion of the work carried out under 

 Mr. Stone's direction at the Cape of Good Hope between the 

 years 1S70 and 1879. The ca ahigue gives the positions of all 

 stars down to seventh magnitude between the equator and 

 N.P.D. 115°, except those in clusters; of fainter stars to fill 

 existing lacunae ; and of many stars of greater N. P. D. than 

 115° for comparison with the Cape catalogue of 1880. Many 

 stars north of the equator are also included. The Cape cata- 

 logue and the present one together give a series of well-distri- 

 buted zero-points for the whole southern hemisphere. With 

 refere'nce to future meridian work, Mr. Stone remarks : " Fiom 

 the facilities which photography affords for the rapid filling in 

 of the positions of the fainter stars on a phoiographic plate, 

 when those of a sufficient number of zero-points on the plate 

 have been otherwise fixed, it would appear that the efforts of 

 meridian observers will, for the future, be most advantageou-ly 

 directed to this class of stellar work." The catalogue includes 

 estimates of proper motions as well as the usual constants, and 

 there are also copious notes relating to the double and variable 

 stars. The early appearance of a catalogue entailing such a 

 vast amount of computation does great credit to the very limited 

 staff of th«-observalory. 



" L'Astronomie." — The decease of this monthly journal of 

 popular astronomy is announced in the December number. 

 For thirteen jears M. Flamniarion has conducted /.'.•/j/»tfHtf«;/f, 

 and has used it to poj ularise, and extend the study of, a>tro- 

 nomical science, and now it dies hom " difficultcs d'adminislra- 

 tion." The Societc Aslrcnomique de France proposes to at 

 tempt to fill the gap by iss.uirg their BttUdin monthly instead 

 of quarterly, as herelolore. 



NO. I3I'?, VOL. 51] 



