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CHEMISTRY. 



gen peroxide in the air and in atmospheric de- 

 posits is the subject of a recent exhaustive re- 

 port by Schone, of Moscow. His investiga- 

 tions extended from July 1, 1874, to June 30, 

 1875, and were conducted with wonderful 

 patience and care. He examined 215 speci- 

 mens ot rain and hail, and snow and sleet 

 were tested on 172 occasions. Seven samples 

 of rain and 86 of snow appeared to contain no 

 peroxide. 



The deposits brought by the equatorial currents 

 always contained more peroxide than those falling 

 at times when the polar currents opposed them ; and 

 when the polar stream of air predominates, the rela- 

 tively smallest yield of peroxide is obtained. The 

 amount attained a minimum in December and Janu- 

 ary, very slowly increased until April, was very much 

 higher during May and June on to July, when it cul- 

 minated. During the next three months it tell rapid- 

 ly, and in November again very slowly approached 

 the minimum. The hail of summer contained a 

 comparatively large amount of the peroxide, although 

 it is less abundant in hail than in rain ; and the 

 winter rain yields more of this compound than snow 

 falling at the same period. The total amount of 

 hydrogen peroxide which reached the earth's sur- 

 face during the year is computed by the author to 

 have amounted to 109'4 milligrammes to the square 

 metre that is to say, in 599'9 litres of water, or 

 1-049 kilog. to the hectare. The peroxide present 

 in the air in a state of vapor was collected and 

 determined by producing artificial dew with the 

 aid of freezing mixtures ; and it was found that the 

 rise and fall in the amount so obtained correspond- 

 ed and went hand in hand with the numbers ob- 

 tained by testing the atmospheric deposits. The 

 diurnal variation was studied, and it was ascertained 

 that the maximum amount was present at about 4 

 o'clock in the afternoon, after which it diminished, 

 the minimum being attained between midnight and 

 4 A. M. The air of a large hall, which had been un- 

 occupied for four weeks and the windows of which 

 were closed but were not air-tight, was observed to 

 contain an average of 0*17 c. c. peroxide in 1 .000 cubic 

 metres. In dew artificially deposited in a badly ven- 

 tilated room there was no peroxide ; its presence, 

 however, became manifest as soon as the windows 

 were thrown open. Dew and hoar frost deposited 

 during the last hours of the night appeared to be pure 

 water; in dew collected during the evening hours 

 peroxide was met with, the amount being 0'05 

 gramme to the litre. The peroxide is present in fop, 

 and is apparently more abundant in spring than in 

 autumn. The amount of peroxide present in any 

 atmospheric deposit varies with the altitude at which 

 that deposit has been formed ; the greater the alti- 

 tude at which the condensation takes place, the 

 greater is the quantity of peroxide which it will con- 

 tain. This is doubtless due to the decomposition 

 which that substance must undergo when exposed to 

 organic vapors rising from the earth's surface. In 

 the air itself there is but little peroxide, the maxi- 

 mum quantity observed being 14 c. c. in 1,000 cubic 

 metres of air. The author points out the scientific 

 advantages which would attend systematic observa- 

 tion in this field at meteorological stations. 



The same author has investigated the rela- 

 tions of hydrogen peroxide to the alkalies, with 

 particular reference to the decomposing action 

 of the latter on the former. Of this research 

 we append an excellent summary, published in 

 the " American Journal of Science " : 



His first efforts were directed to the production 



' of peroxide hydrates of the alkalies analogous to 



those of the alkaline earths. For this purpose a solu- 



tion of hydrogen peroxide containing 3 or 4 per cnt. 

 was mixed with a 10 per cent, sodium-hydrate solu- 

 tion, in equivalent proportions. A rise of 4 or 5 

 C. took place with a very slight evolution of gas. 

 On concentrating the solution in a vacuum, efflores- 

 cent crystals separated on the edges at first, and then 

 large tabular crystals formed in the solution. If, in- 

 stead of evaporating the solution, once and a half or 

 twice its volume of absolute alcohol be added, and 

 it be allowed to stand in a cool place for twenty-four 

 hours, spear-shaped crystals, often several centi- 

 metres long, appear in the solution. On analysis 

 they give numbers agreeing with the formula JSa 2 2 

 (H y O) 8 . They are identical with those obtained 

 later by Fairly in the same manner, and with those 

 obtained by Vernon Harcourt by solution of sodium 

 dioxide in water. When rapidly heated in a glass 

 tube, the crystals melt, froth, evolve oxygen and 

 leave sodium hydrate. In closed vessels, the same 

 decomposition takes place more slowly, requiring 

 three months for completion. Absolute alcohol pre- 

 serves it pretty well, if carbon dioxide be excluded. 

 On examining the efflorescence above mentioned, it 

 was found to be. a mixture of the substance already 

 described and of another substance having the for-' 

 mula Na 2 H 4 O 6 , or Na 2 2 (H 2 2 ) 2 , a compound of so- 

 dium peroxide with hydrogen peroxide. To pre- 

 pare it, a mixture of one molecule of sodium hydrate 

 and about three and a half molecules of hydrogen 

 peroxide solution are mixed and evaporated in 

 vacuo. The crystals are colorless and very minute, 

 are at first transparent, very soluble in water, dis- 

 solve in this and in dilute acids without evolution 

 of gas, and effloresce in dry air. In vacuo over sul- 



Shuric acid they lose four molecules ot water, leav- 

 ig Na 2 H 4 O 6 . A similar peroxide hydrate was ob- 

 tained with potassium, though mixing the solutions 

 and evaporating gave only a yellow amorphous mix- 

 ture of potassium tetroxide and' potassium hydrate, 

 K 2 4 + (KOH + H 2 0) 4 . But if excess of hydrogen 

 peroxide be used, and the evaporation be conducted 

 at a low temperature, - 10 C., a white opaque mass 

 results, which is very hygroscopic and has the for- 

 mula K 2 H 4 O 6 , or K 2 O 2 (B* 2 O2)2. These facts the au- 

 thor uses to explain the "catalytic" action, as fol- 

 lows : The decomposition of hydrogen peroxide in 

 alkaline solutions is due, first, to the tendency of 

 the alkalies to form compounds of the composition 

 E 2 H 4 6 or K 2 O 2 rH 2 2 ) 2 ? second, to the tendency 

 of the alkali metal within this compound to oxidi/e 

 itself to a higher oxide, the tetroxide ; and, third, to 

 the reduction of the tetroxide to dioxide by the water 

 present. 



New Discovery in Thermo- Chemistry. A 

 discovery of importance in thermo-chemistry 

 Las been communicated to the Paris Academy 

 of Sciences, by M. Maumene. Concentrated 

 sulphuric acid, he writes, which has been left 

 for some months standing, undergoes a singu- 

 lar change of condition. On mixing a liquid 

 such as olive oil with, say, one tenth of its 

 weight of fresh concentrated acid, a certain 

 constant rise of temperature is observed ; but 

 if acid three months old is used, the rise of 

 temperature so obtained has a value of about 

 8 Cent. less. The same results occur even if 

 the acid has been hermetically sealed in glass 

 tubes. With water and other liquids analogous 

 results are found. It is evident that some of 

 the most important data of the thermal effects 

 of chemical action may require revising in the 

 light of this discovery. 



New Method of separating Arsenic and An- 

 timony. A new mode of separating arsenic 

 from other metals is offered by Messrs. De 



