COMPANY.

AT the invitation of this company, we

inspected their works at the Square Shot Tower, Waterloo-bridge, on the 4th ult., and it gives us great pleasure to be able to testify to the excellence of the arrangements and the completeness of the process. Having, in our last number, given our opinion of the pavement, we have nothing to add on that head, but feel it incumbent on us to again call the attention of our readers to it.

The

MM. Girardin and Bidard have determined with care the quantity of nitrogen, by means of Liebig's apparatus. They obtained 2.72 per cent. of nitrogen by weight.

The strength of this manure is, then, expressed by the cypher 680.0, and its equivalent by that of 14.70, whence it results that 14 kilogr., 70 of vitriolic ashes of Forges, have as much action with respect to its nitrogen, as 100 kilogr. of normal dung.

Picardy ashes contain, according to MM. Boussingault and Payen, only 0.65 per cent. of nitrogen, and their equivalent is represented by 61.50. The vitriolic ashes of Forges are, therefore, far superior in this respect.

The existence of sulphate of iron in these earths, which is continually reproduced by the action of the air on the sulphuret of iron which exists in it in very fine particles, ex

* Travaux de la Societé d'Agriculture de Rouen, July, 1842.

† See our present Number, page 409.

Fine sand

Insoluble humus

Sulphuret of ironPeroxide of iron

2.74

1.79

38.92

49.83

6.72

100.00

plains the very active properties which they possess, as a stimulant, on natural and arti ficial meadows.

Their powerful efficacy may be referred to several causes :

1. To their dark color, which has great influence on the heating of the earth by the solar rays:

2. To the sulphuret of iron, which, by its slow combustion, increases the heating of the earth and the electrical excitation :

3. To the large proportion of soluble and insoluble humus :

4. To the sulphate of iron, which, besides its property of causing bad herbs, mosses, lichens, &c., to perish, reacts on the carbonate of lime of the soil, and forms sulphate of lime which acts so powerfully on leguminous plants.

From their composition, it is evident, that it is especially on calcareous soils, and on soils frequently limed and marled, that the vitriolic ashes produce the best effects. This has also been demonstrated by experi

ment.

ON GUANO OR HUANO.*

BY MM. J. GIRARDIN AND BIDARD.

UNTIL within the last few years, we never thought of employing guano as a manure. Some English vessels, coming from the coasts of Peru, having brought over large quantities of it as ballast many experiments have been made in England, and the results have greatly exceeded the hopes of agriculturists, who bear witness to the superiority of this manure. 200 kilogrammes of guano and 25 or 30 kilogrammes of charcoal are sufficient for manuring an hectare of corn land.

The sample operated on by MM. Girardin and Bidard, at the invitation of the Société d'Agriculture de Rouen, was a coarse brown powder, exhaling a strong and fetid odor. Two quite distinct parts could be mechanically separated from it :

1. A humid brown dust, containing a large quantity of carbonate of ammonia :

2. Small, whitish, semi-hard grits, which differed from the above dust only by the total absence of carbonate of ammonia. These small grits were analysed, and the following are the substances which they contained :

:-

of birds: but as, according to the observations of Baron Humbolt, the Ardea and Phenicoptera, which inhabit the islands of the South Seas, could not produce such immense masses of guano as those which exist in these isles. MM. Girardin and Bidard state this new opinion; that guano does not belong to the present period, and that it is a coprolite, or fossil excrement of ante-diluvian birds.

The presence of carbonate of ammonia in the fine dust separated, by sifting from the grits, is purely accidental. It is probable that it is the product of the decomposition of urate of ammonia, which is easily effected under the influence of atmospheric humidity. This opinion is corroborated by the fact of the grit, when exposed to the contact of the air, speedily dilating and falling to dust, which then contains much carbonate of ammonia, which may be isolated and sublimed by means of a gentle heat.

Of all the principles which constitute guano, the most important one, without doubt, is uric acid and ammonia. It is to their presence, and especially to their abundance, that the very great fertilising properties of this plant must be attributed. If, as cannot be doubted, the value of manures depends greatly on the proportion of nitrogen that they contain, and if the rapidity of their action on vegetation, is in direct ratio to the facility with which they yield to plants their soluble or gasifiable nitrogenous principles, it is easy to comprehend the superiority of guano over most other manures, and the promptitude with which it operates. It is absolutely in the same condition as columbine or pigeons' dung, whose chemical nature is identical, except that the latter contains a smaller proportion of ammoniacal compounds.

In order to determine the value of guano as a manure, MM. Girardin and Bidard estimated the uric acid and ammonia found in it. Their analysis showed that 100 parts of guano by weight contained :

indeed, only 4.97 per cent. of nitrogen in normal or crude guano; and 5.39 per cent. of nitrogen in guano sifted, and separated from dust.*

Again, while MM. Boussingault and Payen give for the equivalent of sifted guano the cypher 7.41, according to MM. Girardin and Bidard the equivalent of the same substance would be 2:37.

[The proportion of nitrogenous matter contained in guano, by which alone its value as a manure is estimated, is so very variable as to render it exceedingly injudicious for agriculturists to purchase it without first having it analysed. It should be paid for only according to its useful contents. Not only do the analyses of Fourcroy and Vauquelin, Boussingault and Payen, Girardin and Bidard, and Wöhler, vary considerably, but those of Mr. Johnston, and the late Mr. Henryell show very different proportions of nitrogenous matters. From very numerous analyses of guano which we have ourselves performed, we are enabled to assert that no two samples are of the same value. We advise our agricultural readers not only to have the guano analysed by a chemist practically acquainted with the analysis of this complex substance, but also to pay for it only according to its real value as a manure.-Eds.]

other objections to the opinions which he combats. It is no longer a question of the total absence of fatty matters in those aliments, but the proportions and properties of these matters."

I may be allowed to remark to the Academy, that the analyses of MM. Dumas and Payen which have come to my knowledge, are reduced to a determination of the matters soluble in ether which hay and maize contain. I am ignorant of the other analyses of these gentlemen, which have led them to admit that the grass and roots eaten by cows contain butter, and that the food given to cattle, contains beef fat. I have denied and I again deny the presence of fats (combinations of fatty acids with glycerine) in the nourishment of the cow and of the ox; I deny the presence of bile (or rather of the matters soluble in ether, contained in bile) in the same nourishment; I deny the presence of fish oil and of spermaceti in sea plants; but I voluntarily admit, with fifty other chemists, that grass and green leaves contain green wax, commonly called chlorophylle, and my own investigations have put me in a position to confirm the discovery of the excellent observer Proust, that provender, the green leaves of cabbages, of the Graminaceæ, cherries, and prunes, contain a

white wax.

I am, indeed, astonished that the presence of this wax in hay and potatoes should have escaped the observation of such experienced chemists, for they have made no mention of it in the two memoirs which they have read before the Academy; and it was only after I had called their attention to

ANIMALS.*

BY PROFESSOR LIEBIG.

Ar the sitting of March 6, M. Dumas expressed himself with respect to the opinion which I have formed on the origin of fat in herbivorous animals, in the following terms. (See THE CHEMIST No. XLIII., N. S. No. VII. p. 318.):

"As soon as he was acquainted with our analyses of provenders, Professor Liebig hastened to repeat them, and in this case, as in that of maize, he has ascertained their accuracy; he was therefore mistaken in denying the existence of fatty matters in the aliments of herbivora. But he now states

* Annales de Chimie, 3e Serie, annee, 1841, t. iii. p. 105. [There must be some mistake in this reference: there is nothing about guano on the page in question, from which we have translated the synoptical of this equivalent of various manures. (See page 408 of the present number.-EDS.]

M. Payen quoted at the sitting of the 6th of March, an incorrect passage, that they hastened to modify their new theory. I am, in fact, inclined to believe that M. Dumas, in giving his opinion concerning the origin of fat in animals, had not made any experiment on the subject, for he informed the Academy at the same sitting, that he, M. Boussingault, and M. Payen, had simply adopted the plan of Gmelin and Tiedemann, who suppose the fatty matters to be ready formed in the aliments. The avowal of these gentlemen, that this theory belongs not to them, but to my illustrious countrymen, appears to me somewhat late; but it is true that they have now to partake a certain responsibility.

In the experiment which I have related in my letter, (see THE CHEMIST, NO, XLIII., N. S. No. VII. p. 315), a cow which ate, on the estate of M. Koch, at Giessen (15 kilogr. of potatoes and 7 kil. 500 of hay) received in its food in six days, according to my analyses, 756 grammes of matters soluble in ether, and in its excrements the same cow