64 



NATURE 



[May i;, 1894 



Reeve, and Hen Harrier. Though it may be thought a little 

 " previous" to refer to some of these species as lost, there are 

 others, such as the Goshawk, Night Heror, Little Bittern, and 

 Baillon's Crake, not included in the list, but which there is 

 reason to believe were once summer residents and breeders 

 in Great Britain. It is often remarked that the total disappear- 

 ance of some species of birds, and the extreme rarity of others 

 once common in this country, is due to the draining of marshes 

 and similar changes on the face of the land. But the facts 

 brought together by Mr. Hudson show that the disappearances 

 have been mostly brought about by the direct action of those 

 inveterate bird-destroyers, described as "The Cockney sports- 

 man, who kills for killing's sake ; the gamekeeper who has 

 set down the five-and-lwenty most interesting indigenous species 

 as 'vermin' to be extirpated ; or, third and last, the greedy 

 collector, whose methods are as discreditable as his action is 

 injurious." If these and others who have helped to degrade 

 the character of our bird-population will read Mr. Hudson's 

 little pamphlet, they will see the greatness of the change that 

 has taken place. 



FfRTiiER interesting properties of sodium peroxide are 

 described in the current Berichte by Prof. I'oUck, of Breslau. 

 It is shown that sodium peroxide rapidly reduces salts of gold, 

 silver and mercury with separation of the metal and evolution 

 of oxygen ga«. Platinum, however, is not precipitated from 

 chloroplatinic .icid or chloroplatinates until they are decomposed 

 with a silver salt, when reduction both of the resulting platinum 

 chloride and of the silver chloride occurs, both metals being 

 precipitated. Ferric hydroxide is precipitated, as might be 

 expected, from both ferrous and ferric salts ; from manganous 

 salts manganese dioxide is precipitated, presumably hydrated, 

 and from salts of cobalt the higher cobaltic oxide. Permanganates 

 are reduced to manganese dioxide, but chromic oxide is oxidised 

 to chromic acid. The separation and quantitative estimation 

 of iron and chromium or manganese and chromium are easily 

 achieved by utilising these reactions, for iron is precipitated as 

 ferric hydroxide and manganese as peroxide, while chromium 

 remains in solution as chromate of sodium. .Sodium peroxide 

 also produces the highly oxidised sodium peruranale, Na^U-jOg 

 -i-8II._.0, directly from salts of uranium, and it may readily be 

 isolated by addition of alcohol which precipitates it. It is also 

 interesting that iodine is oxidised on warming directly to the 

 difficultly soluble acid sodium periodate, and upon decomposition 

 of this salt with silver nitrate the normal silver periodate is at 

 once produced, and free periodic acid HIO^-J- 2lI.jO may be 

 readily obtained from it in large crystals by decomposition with 

 bromine and subsequent evaporation in vacuo. Potassium 

 ferricyanide behaves towards sodium peroxide in a similar 

 manner to its action with hydrogen peroxide, reducing it ener. 

 getically to fertocyanidc, and the volumetric process of Kassner 

 can be readily carried out by use of it. Sodium peroxide reacts 

 with lead oxide in presence of water to produce a plumbale of 

 lodium of the composiiion Na.jPLO, l-4ll,0. Organic com- 

 pounds dissolved in alcohol are usually very rapidly oxidised by 

 sodinro peroxide, while the alcohol itself is not attacked. Kther, 

 on the contrary, at once ignites when brought in contact with 

 the peroxide. Prof. Polcck recommends its use likewise in the 

 separation of arsenic, antimony and tin, for the sulphosalls of 

 these elements are at once oxidised by sodium peroxide in pre- 

 sence of water to oxygen compounds, the whole of the sulphur 

 being simultaneously converted into sulphuric acid. Hence in 

 toxicological investigations it is only necessary to oxidi>e the 

 sulphosalti with sodium peroxide before proceeding immediately 

 to employ Marsh's lest. The practical uses of sodium peroxide 

 appear indeed to be very numcrouf, and the information now 

 rapidly accumulating concerning it will doubtless prove of 

 ralue t)oth from the theoretical and the technical point of view. 



NO. I 28 I, VOL. 50J 



I.v our note concerning the atomic weight of barium (vol. 

 xlix. p. 562), the slalement that "the highest and lowest indi- 

 vidual values obtained among the whole fifty separate estimations 

 were 137-42 and 137-45 " should have read " the highest and 

 lowest of the mean values obtained from the different series of 

 estimations were 137-42 and 137-45." 



The additions to the Zoological Society's Gardens during 

 the past week include a Moiambique Monkey (Cinopitlucus 

 fygen'thrus, ? ) from South-east .\frica, presented by Mr. H. 

 Taltenhall ; two Laughing Kingfishers {Oacdo gigatileiis), two 

 Berigora llaviVs (Hieracia'ea btrigora) (lom Australia, presented 

 by Mr. A. E. Henniker ; seven Spanish Blue Magpies ( Cyano- 

 /o/iiis I ooii) Com Spain, presented by H.R.H. the Comte de 

 Paris ; a Tuatera Lizard {S/^hoioUoii punctatns) from New 

 Zealand, presented by Dr. \V. J. Mackie ; an Egyptian Terra- 

 pin ( Trionyx ccgyplicus) from West Africa, presented by Mr. 

 F W. Mar>hall ; a Green Lizard (J.acerla viri,lis) European, 

 presented by Miss S. Borgaes, a Yellow-billed SheathbiU 

 {Chionis alba) from Antarctic .\merica, a Red and Blue Macaw 

 (Ara mcu-ao) from South .\merica, a Black Iguana {Mtlopoceros 

 cornulus) from San Domingo, a GeofiVoy's Terrapin {HyJratpis 

 geoffroyana) from Trinidad, seven Say's Snakes {Coraiulla sayi) 

 from North America, deposited ; a Derbian Wallaby {Halma- 

 tunts derbianiis, i ) born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



Fi.nderCirci.es FOR Equatouials. — .V very ingenious and 

 what may prove a most u-eful addition to an equatorial are the 

 so-called star-dials or finding-circles, a brief .iccount of which 

 is contributed to the current number of the Zcitichrift fiir 

 Inslrtimenttnkundc {4 Heft, April 1894). Every worker with 

 the equatorial will no doubt al some time have found out that 

 the present mode of setting the instrument on some object, .as, 

 for instance, a star, is not always very convenient, and in addition 

 employs comparatively far too much time. The object of these 

 finding-circles is to reduce this time very cr)nsiderably, and a 

 use of three years has shown that its aim has been successfully 

 attained. The instrument to which it has been applied is the 

 1 2-inch of Georgetown College Observ.-itory, Washington. 

 On the pillar of this instrument are the two hand-wheels, by 

 means of which the telescope is moved in right ascension and 

 declination, and also two microscopes for reading the R. A. 

 circle. Both axes of the telescope carry the usual circles for 

 orientation, each being graduated in fine divisions on silver and 

 large white divisions on a dark background. The finding-circles 

 are situated just above the hand-wheels mentioned above, and 

 fixed to the pillar, looking like a pair of aneroid b.irometersor 

 steam gauges; ihey are arranged as follows: — The circular 

 divided disc, with ilie declination divisions arranged round its 

 circumference, is fixed firm in its case, and the index is so 

 geared to the telescope that any movement of the latter is 

 recorded on the dial ; this gives one directly the declin.ation. 

 In the case of the other dial, that for right ascension, the disc 

 is divided into two circles of twelve hours each, and instead of 

 being fixed is moved by clockwork, siilercal time being shown on 

 its face by means of another index ; thi-i latter inlex re-iponds also 

 to the movement of the telescope, but is ')uite independent of 

 the first one. It will at once be seen that with these two dials 

 so conveniently placed the telescope can be at once oriented, 

 while the question of hour-an'^lc is entirely eliminated. 



The IIarvarii Ouservathrv in Peru. — .An historical 

 skelch of the est.iblishment of the Peru branch of the Harvard 

 College Observatory, and the investigations carried on there, 



' is contributed to the Ilanatd Giaduatis' /l/(Ji,'as;«<- for M arch 

 by Prof. W. H. Pickering. The Observatory is situated about 

 two miles from Arequipa, and four hundred feet above i', on 

 the slopes of Mount Chachani. It is furnished wiih a very 

 complete instrumental outfit, the most important instrument 

 being a 13-inch equatorial, capable of being used for either 

 visual or photographic purposes, and an 8-inch photographic 

 telescope. Five meteorological stations have been established 



I by the Observatory. One is at Mollcnd«, on the sea-coast, 100 



