10 



MODE OF MANUFACTURING ARTIFICIAL ESSENCES. 



[1853 



lime and magnesia, to an extent scarcely to be credited, were it 



not the actual result of experiment. Taking the a-, erage of these 

 analyses, and reducing tlie French weights to our own standard 

 of 7,000 grains to the pound, it will be seen, in these six months, 

 the rain which fell on a space of ground at the Observatory at 

 Paris, eqnal in area to an English acre, contained, as nearly as 

 possible, 7.75 pounds of ammonia; 36.50 pounds of nitric acid; 

 5.5(5 pounds of chlorine; 12.00 pounds of lime; 4.81 pounds of 

 magnesia. 



From July to December is usually the drier half of the year, 

 as well as that in which the less fuel is consumed, so that we may 

 safely double these quantities, in estimating the annual supply 

 per acre of nitrogeneous compounds, gradually distributed o\er 

 the country by the rain. For the sake of illustration, we have 

 calculated "the amount of the solid constituents of the rain falling 

 on an area equal in extent to Great Britain, and balancing the 

 various causes likely to lessen or to increase the quantity of these 

 matters, which would so fall on this island, we may venture to 

 set one against the other, and apply the above statement to our 

 own country, as the basis of an estimate, which singularly mani- 

 fests the " power of littles,'" as well as the grand scale on which 

 even the minutest of natural phenomena proceed. Thus, on the 

 Parisian data, the weights of these fertilizing materials annually 

 supplied to the soil of this island by the rain, amount to about 

 400,000 tons of ammonia; 1,850,000 tons of nitric acid; 279,- 

 000 tons of chlorine; 640,000 tons of lime; 244,000 tons of 

 magnesia. 



Making every allowance for errors of experiment, which, how 

 ever, would rather increase than diminish these quantities, except- 

 ing, it may be, the amounts of the two last on the list, these re- 

 searches of M. Barral prove to us that, the amount of fertilizing 

 matter conveyed to the soil by the rain, must exercise a constant 

 and most important influence on the vegetation of a country. 

 These facts also tend to throw still further doubt upon the pecu- 

 liar efficiency of the salts of ammonia, and of the acid of the ni- 

 trates as manures; for we find in rain-water a constant supply of 

 these nitrogeneous matters, not applied once, or at most twice, in 

 the year, as is the case with the various artificial manures, such as 

 the nitrates of potash and of soda, Peruvian, and those guanos 

 which contain a large proportion of soluble ammoniaeal salts, and 

 the various ammoniaeal composts, made and sold in this country, 

 the utility of which must chiefly depend on the concurrence of 

 several favorable conditions of the plants, the soil and the weather ; 

 for we find that the nitrogen required for the growth of the plant 

 is supplied in the fittest state for assimilation (viz., that of great 

 dilution,) and at all stages of its growth, by every shower that 

 falls. The later opinions entertained by Liebig, of the superior 

 value of the alkaline and earthly constituents ot manures, i. e~, the 

 potash, soda, lime, magnesia, and the phosphates and sulphates of 

 these bases, to that of their nitrogeneous compounds, derive much 

 weight from these experiments of M. Barral, which show that a 

 vast amount of nitrogeneous fertilizing matter is distributed by 

 the rain but none of the fixed alkalies, or of the salts of phospho- 

 ric and other acids, equally important to the due growth of veg- 

 etables, and which, unless naturally existing in sufficient amount 

 in the soil, must be supplied by the application of manure, or the 

 plant will either dwindle, or yield an imperfect produce, owing to 

 an insufficient supply of one portion of its requisite constituents, 

 however much it may be stimulated by an abundant application 

 of ammoniaeal fertilizers. The prevailing use of these manures, 

 which are so highly charged with the salts of ammonia, readily 

 account for the increasing " steeliness" which is observable in 

 English wheat, arising in great measure, as remarked by Liebisj, 

 from a superfluous and unnecessary supply of the ammoniaeal 

 stimulants, and a deficiency in the more important constituents of 

 the cereals, viz , the «arthy phosphates and alkaline salts, which 



are not brought to the growing corn in the rain, like the nitro 

 geneous constituents. — London Critic. 



Cu Oxygen, by Professor i'ura-'ay. 



Royal Institution, June 22nd. 

 The object of the speaker was to bring before the members, in 

 the first place, M. Boussingault's endeavors to procure pure 

 oxygen from the atmosphere in large quantities; so that being 

 stored up in gasometers it might afterwards be applied to the 

 many practical and useful purposes which suggest themselves at 

 oiue, or which may hereafter be developed. The princij lc of 

 the process is to heat baryta in close vessels and peroxidize it by 

 the passage of a current of air; and afterwards by the applica- 

 tion of the same heat, and a current of steam (with the same ves- 

 sels), to evolve the extra portion of oxygen, and receive it in fitly 

 adjusted gasometers: then the hydrated baryta so produced is 

 dehydrated by a current of air passed over it at a somewhat 

 higher temperature, and finally oxidized to excess by the continu- 

 ance of the current at a lower temperature: and thus the pro- 

 cess recurs again and again. The causes of failure in the pro- 

 gress of the investigation were described as detailed by M. Bous- 

 singault ; the peculiar action of water illustrated ; the reason why 

 a mixture of baryta and lime, rather than pure baryta, should be 

 used, was given; and the various other points in the Memoire of 

 M. Boussiugault were noticed in turn. That philosopher now 

 prepares the oxygen for his laborotory use by the baryta process. 

 The next subject consisted of the recent researches of MM. Fremy 

 and E. Becquerel " On the Influence of the Electric Spark in 

 converting pure dry Oxygen into ozone." The electric discharge 

 from different sources produces this effect, but the high intensity 

 spark of the electric machine is that best fitted for the purpose. 

 Wheu the spark contains the same electricity, its effect is propor- 

 tionate to its length ; for at two places of discharge in the same 

 circuit, but with intervals of 1 and 2, the effect in producing 

 ozone is as 1 and 2 also. A spark can act by induction; for, 

 when it passes on the outside of a glass tube containing within dry 

 oxygen, and hermetically sealed, the oxvgen is partly converted 

 into ozone. Using tubes of oxygen which either stood over a 

 solution of iodide of potassium or, being hermetically sealed, con- 

 tained the metal silver, the oxygen converted into ozone w T as ab- 

 sorbed; and the conversion of the whole of a given quantity of 

 oxygen into ozone could be thus established. The effect for each 

 spark is but small; 500,000 discharges were required to convert 

 the oxygen in a tube about 7 inches long and 0.2 in diameter 

 into ozone. For the details of this research, see the " Annales 

 de Chimie" 1852, xxxv. 62. — Mr. Faraday, then referred briefly 

 to the recent views of Schonbein respecting the probable existence 

 of part of the oxygen in oxy-compounds in the ozone state. 

 Thus of the peroxide of iron, the third oxygen is considered by 

 him as existing in the state of ozone ; and of the oxygen in per- 

 nitrous acid, half, or the two latter proportions added when the 

 red gas if formed from oxygen and nitrous gas, are supposed to ' 

 be in the same state. Hence the peculiar chemical action of those 

 bodies ; which seems not to be accounted for by the idea of a bare 

 adhesion of the last oxygen, inasmuch as a red heat cannot sepa- 

 rate the third oxygen from the peroxide of iron ; and hence also, 

 according to M. Schonbein, certain effects of change of colour by 

 heat, and certain other actions connected with magnetism, &c. 



Mode of Manufacturing Artificial Essences. 



Prof. Fehling, in the Wurtemberg Journal of Industry, gives 

 the following abstract of what is at present generally known res- 

 pecting the composition and production of some of the artificial 

 extracts of fruit. He says : 



Amongst the chemical preparations exposed at the London 



