vegetable nutrition to believe that the least soluble salts (so that they be soluble in some measure) are the most adapted for the supplying the mineral matters of plants. The quantity of water passing through a plant, and expaled by its leaves, during the period of its growth, is very great. From some experiments made by Mr. Lawes on this subject, we may infer that a wheat crop exhales in its growth as much as 230 times its weight of water; and it is plain that this water must be charged with the soluble matters of the soil.

Silicate of lime, like many other slightly soluble salts, is more soluble in solutions of other salts than in pure water. For instance, in a weak solution of common salt it dissolves to twice the extent that it does in plain water: it is also much more soluble in water containing carbonic acid. But, calculating the quantity dissolved by water only, we should find that, during the growth of a crop of wheat or barley, enough silica might be introduced in the form of silicate of lime for the necessities of the plant.

We believe, therefore, that such silicate of lime will be found to be sufficiently soluble for agricultural use. At the same time its value as a manure can only be ascertained by practical experiment.

It is notorious that the growth of wheat is chiefly uncertain on light sandy or peaty soils; the difficulty is not so much the production of the plant as that of bringing it to maturity, and preventing it from being lodged or laid before harvest. This condition of the plant is usually attributed to a deficiency of silica in the straw; and although there is no very good evidence to prove that the quantity of silica is actually less in such straw than in that which is strong and bright, it seems very reasonable to suppose that a want of silica, or indeed of any other of the necessary ingredients of the plant, would lead to an unhealthy and immature state, and indirectly we should therefore be right in referring the evil to such a cause.

We have observed that silicate of lime has the peculiar property of decomposing ammoniacal salts. When mixed, for instance, with sulphate of ammonia it causes an instant disengagement of ammonia, in the same way, though in a much less degree, than caustic lime itself would. The change that occurs here is the formation of sulphate of lime and silicate of ammonia; but the latter, being a very weak salt, breaks up quickly into free ammonia, which escapes into the air, and silica. If the solution of silicate of ammonia is very weak, however, this decomposition of the silicate of ammonia does not appear to occur.

It is very probable that silicate of lime may in this way serve an important purpose in light soils. If, as Mr. Way has urged in former papers, crude ammoniacal salts are positively injurious

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to plants, and that in good loamy soils they are modified and changed into slightly soluble silicates, it will evidently be an approach to this condition, if in light soils we can induce the conversion of the different salts of ammonia into the form of silicate of ammonia, which is believed to be the actual form in which in good soils it is presented to the roots.

The simple silicate of lime of which we are now speaking must not be confounded with the compound form-silicate of lime and alumina : this latter actually, as we have before seen, separates and renders insoluble the ammonia of manure; silicate of lime will not do this, and it cannot be looked to as a means of making light land more retentive of manure; but if, as we hope, it should be found to render the use of nitrogenous manures, such as guano, &c., more safe on light land, and should facilitate the growth of large crops on such lands by the use of abundance of manure, a great advantage would be obtained for the agriculture of this country. We think, therefore, that silicate of lime is well worth trying as a means of brightening and strengthening the straw of cereal crops on light land, and of checking the over luxuriance due to high manuring. It might be made very cheaply-probably at a cost of less than 37. per ton-and from 2 to 3 cwt. would be a sufficient application per acre. It might

be applied either in the autumn or as a top-dressing in early spring; but, from its comparative insolubility, it would be better to have it well diffused through the soil, and therefore the autumn would probably be the best time for applying it.*

We have already mentioned the advantage obtained by the application of lime on those lands where this rock shows itself near the surface: for the districts where it is easily obtained it may be often desirable to apply the silica marl with lime, either separately or at the same time, trusting to the combination taking place in the soil. Where lime-kilns exist in these districts, a very easy method of forming the silicate would be to heat gently the building-stones (Nos. 54, 60, 76, 77) which we have described as containing carbonate of lime mixed with soluble silica. The burning will be effected in the same way as that of common chalk, but at a lower temperature.

The discovery of these silica beds brings us a great way nearer

On the 12th April in this year, upon some wheat grown on a gravelly soil, resting upon the lower greensand, naturally poor but well cultivated, and manured with dried blood at the rate of 5 cwt. per acre, was applied on 10 perches 28 lbs. of the double silicate of alumina and ammonia; two perches were then missed, and on another 10 perches 60 lbs. of silicate of lime was applied; two perches were again missed, and on a third plot of 6 perches 39 lbs. of silicate of soda was applied. At this time (8th June) all the three plots are manifestly better than the unsilicated portions, the straw being from 4 to 6 inches higher, and not quite so dark a colour. -J. M. PAINE.

to the practical production of the double silicates for agricultural use, but we shall probably have to return to this subject in a future paper. We have only further to add one or two remarks on the formation of this silicious deposit. It is not infusorial; for, with the exception of a few foraminifera, no traces of animal life can be observed in the rock by microscopical examination. It cannot have been subjected to heat of any intensity, or it would have been rendered insoluble in alkalies. It is plainly the result of aqueous decomposition; and it seems very reasonable to suppose that silicate of lime in solution, derived from the older rocks, may have met with carbonic acid, produced either by vegetable and animal decay, or by volcanic agency, and at one and the same time carbonate of lime and gelatinous or soluble silica would be formed. It should be remembered that we find these beds in immediate contact with the chalk. We find chalk without silica-silica without chalk; and in other cases, as in the building-stones, we have both intimately blended. There is, therefore, very good reason for supposing that these productions have been in some way connected.

This is a speculation, however, of no great interest to the agriculturist, and we shall not carry it farther in this place.

We think it right to state that the subject is by no means exhausted; but having given the results of our investigation up to the present time, as it is obviously connected with many important agricultural questions, we shall probably give an account of our extended inquiries on a future occasion.

"Alton, June 10th, 1853.

"MY DEAR SIR,-A pressure of different professional matters has prevented my attention to your request before. I inquired of Mr. Wm. Pamplin, of River Hill Farm, at Binsted, as to the effects of lime on the malm lands in his occupation at that place. He states as follows:

"The beneficial effects of lime as a dressing on the malm lands would scarcely be credited if not seen: there is no dressing like it. The lime I have applied was white lime from chalk procured at Foyle-white chalk with flints. I have usually applied 1 bushel per rod, and its effects are perceptible for 8 or 10 years; it can be seen to an inch where it has been laid by the luxuriance of the crop, and it can even clearly be perceived where the dust only has settled when the dressing was applied to other land. In one field of mine a small part was missed in the last season-the wheat failed on that spot of the field only. I am certain there are 500 blades on the limed part to every 100 on the part not limed.'

"Mr. John Waterman, of Norton Farm, Selborne, in answer to similar inquiries, states as follows:

"Part of the land in my occupation is malm land, on which I apply a considerable quantity of lime, which works well, particularly for green crops, and makes the berry of the cereal crops much finer. I have used it on the clay lands, but with little advantage. The lime I use is made from the chalk of Noah Hill-principally white. There is grey chalk under the white at

Noah Hill, which makes better lime for building purposes, I think. I had seen no experiment tried till last year, when I used lime from this grey chalk; at present I cannot see any difference in the effect-there are flints in

each sort.'

"If I can make any further inquiries for you, I shall have pleasure in doing so. I remain, my dear Sir, yours very truly,

"J. M. Paine, Esq."

"JAMES W. CLEMENT.

XIX.-Second Report on the Prevention of Pleuro-Pneumonia in Cattle by Inoculation. By Professor SIMONDS, Veterinary Inspector to the Society.

In the former Report which we had the honour of submitting to the Council of the Royal Agricultural Society on the subject of inoculation of cattle as a preventive of Pleuro-pneumonia, we drew attention to the proceedings which had been adopted on the Continent, and more particularly in Belgium, towards establishing this method of imparting security against that insidious and fatal disease. From the great interest which this subject has excited both on the Continent and in England, it becomes necessary to repeat in this place that the plan of inoculation. originated with a Dr. Willems, of Hasselt, who was induced to practise it after giving trial to various other measures; all of which had failed to arrest the progress of Pleuro-pneumonia. Dr. Willems' experiments date from December, 1850, but they were chiefly carried out during the years 1851 and 1852, and were at first made on animals belonging to his father—a distiller and large proprietor of "fatting cattle."

With the introduction of inoculation the attacks of the disease rapidly diminished, and, it being considered that this beneficial change depended entirely on the employment of inoculation, Dr. Willems lost no time in calling the attention of the Belgian Government to the subject. The immediate effect of this step was, as stated in our former Report, the appointment of a Government Commission, consisting of both scientific and practical individuals, to investigate the merits of this new preventive system. This procedure on the part of the Belgian Government led, as was to be expected, to similar Commissions being instituted by other Governments, thereby giving a worldwide fame to the subject of cattle inoculation.

Perhaps, of late years, few things connected with the diseases of cattle have excited so lively an interest or led to more numerous experiments than this supposed preventive of Pleuropneumonia. Under such circumstances it was not unreasonable to hope that, ere this, the question of the propriety of

inoculation would have been both finally and satisfactorily set at rest. It appears, however, that such is far from being the case, and the subject seems destined, for a time at least, to hold its place among the questiones vexate. Men of equally great repute in the science of medicine are to be found ranked on either side, as its advocates or its opponents.

Reserving for the present the opinions which have been formed from our own experience in inoculation, we shall proceed to give the conclusions of other investigators. This becomes the more necessary, as in many particulars a want of agreement would seem to exist even in the results themselves of the operation, and hence probably the cause of the differences of opinion to which we have alluded.

First, in order of time, come two Reports from the Dutch Commission, dated respectively September 21st and December 28th, 1852. The details of the experiments are very accurately given, and occupy the greater part of both reports. It is, however, not necessary to quote them here, as they differ not essentially from those to be afterwards mentioned. "The result of the trial," says the Committee, "may be thus summed up:"

"1st. Although inoculation in pulmonary disease is not, in every respect, a harmless operation, and may produce considerable ulceration, and even death, the symptoms, as a rule, are confined to the part where it is applied.

"2nd. To obviate, as much as possible, unfavourable consequences, it is necessary to use some precaution, as well in regard to the choice of matter as to the time of applying it. The season of the year-the state of the weather -the healthy condition of the animal-may exercise considerable influence. The autumn appears, for several reasons, to be the most fitting time.

"3rd. Where more violent action and dangerous symptoms in remoter organs likewise appear, they may also be connected, excepting in exterior circumstances, with the individual condition of the animal, for which reason they cannot always be avoided.

"4th. When the violent action occurs and extends to the more vital parts, affecting the whole system, its progress can as little be prevented and checked as the disease in general can be cured.

"5th. In those cases where the progress has been serious and even terminated in death, morbid degeneration has never been observed in the pectoral cavity or in the lungs, but as yet only in the cavity of the belly.

"6th. Inoculation, when its effects appear as a local affection, has never exercised any unfavourable influence on the general state of health or on the milk. In those cases only where, on account of previous violent action, fretting ulcerations appear, the animals continue to pine for a while.

"7th. On the procreative impulse it does not exercise any decided influence, being proportionally more prevalent with inoculated than with not-inoculated animals. It is, however, remarkable that it has not occurred with No. 25,* although the regular period is already past.

"8th. The unproductive effects on Nos. 5 and 12, consequent probably on abortion, cannot, as long as these two cases remain isolated, be ascribed to

This and all subsequent numbers named in the extract have reference to animals alluded to in other parts of the Report of the Commission where the details of each case are given.