ments become obvious, and I am satisfied that, so soon as experimenters have had practical experience of the economy of time and money, coupled with the precision they offer, that for all ordinary purposes large experiments will be abandoned. II. ON THE COMPOSITION OF THE BEAN PLANT AT The researches contained in the following pages form part of an extensive series of inquiries which have occupied my attention for some years, and have for their object the investigation of the different agricultural plants at successive periods of their growth, and of which the results for the turnip and wheat crops have already appeared in the 9th and 10th volumes of the Transactions. Such inquiries are necessary to fix some of the great fundamental facts of scientific agriculture. They afford information regarding the period of active growth, the time when valuable matters are most rapidly absorbed from the soil and the air, their distribution through the different organs of the plant, and the proportions in which they are contained in it when it has reached maturity. All these are facts from which most important inferences may be drawn as to the time and quantity in which manures should be applied to these crops, and which throw light on many other important practical questions. In the papers already referred to, I have pointed out some of the bearings of these inquiries, and it will not be necessary to enter upon their consideration at the present moment; but, as an illustration of the nature of the facts which are brought out, it may be mentioned that the investigation of the wheat crop has shown, that contrary to the received opinion, the active growth of that plant is really confined within a very limited period of time, and indicate the importance of assisting its rapid growth by the application of manures at a somewhat advanced period of the season. The bean plants which formed the subject of examination were grown in the year 1864, at Grange, Kilmarnock, on a reddish brown clay loam, of about 12 inches deep, resting on a subsoil of yellow clay, containing many small trap boulders, and having a thin stratum of moss about four feet down. The field bore mangold in 1862, wheat in 1863, and being in a high state of cultivation, no manure of any kind was applied to the bean crop, as it was feared that the straw might be over-luxuriant. The variety of bean used was the common Scotch or horse bean, and they were sown on the 21st April. During the early part of the season the plants made good progress, and gave แ promise of a fine crop; but, during the autumn, the weather in Ayrshire proved most unfavourable to the bean, and it was not till the beginning of November that the produce was harvested, and it was then found to be under the average in quantity, and very inferior in quality. As soon as the plants had attained a sufficient height to admit of its being done conveniently, the number growing on a fraction of an acre was carefully counted, and was found to amount to 100,125 per acre. As this differs very little from 100,000, this round number was assumed as the actual produce, as it involved no appreciable error, and greatly facilitated the calculations, which are tedious and troublesome. On the first of each month, commencing in June, a number of the plants were carefully pulled up, the soil shaken from their roots, and at once packed in a large tin box, with close-fitting lid, made expressly for containing them, and in which they could be conveyed to the laboratory without risk of losing moisture, a precaution which was very necessary, as, in consequence of their being conveyed some distance by railway, nearly 24 hours generally elapsed before they came into my hands. The arrangement was perfectly successful; in fact, the dew still lay on the leaves when the samples reached me. As soon as they were received, the plants were carefully separated, and wiped with a soft cloth. One hundred average plants were then taken and divided into their separate parts. The roots were separated, washed, and dried, so as to remove as thoroughly as possible the soil which adhered to them; the leaves, stems, and other parts were then weighed, and small portions carefully selected, so as to give a fair average of the whole, were weighed out and set to dry, at 212°, in the water bath, for the per centage of moisture. The remainder was spread out on a net placed in a moderately warm place, with free access of air, and when sufficiently dry, was burned in a platinum basin, to obtain the large quantity of ash required for its complete analysis. The residue, dried at 212°, was used for the estimation of nitrogen and the per centage of ash. All these determinations were made in the usual manner, and do not call for any particular notice. 1st Stage, 1st June, 1864. At this period the plants had attained an average length, including roots, of about 10 inches. The stem was soft, and from 4 to 6 leaves, with small buds at the upper part, had been produced. The seed bean still adhered to the roots, but had shrivelled up; and, in some cases, little more than the outer skin remained. They were, however, separated and weighed. One hundred plants gave the following weights in grains: The total produce per acre at this period amounts to 1487-57 lbs., which is divided between leaves, &c., in the following proportions : Roots Seed beans lbs. 449.57 305.00 517.00 116.00 The separate analysis of these organs gave the subjoined numbers :— The same numbers calculated on the dry matter Albuminous compounds 28:37 23.31 Ash Nitrogen 34.36 65.29 55.30 } 94.05 12.30 From these results the weight in pounds per acre of the different constituents of the produce are calculated in the following In examining into the detailed composition of the mineral constituents of the plants, it was found that no results of value could be obtained from the analysis of the ash of the roots; because, however carefully they were washed, it was impossible to free them entirely from soil without injuring them. The In consequence of an accident, and failure of material, it was impossible to make a determination of nitrogen in this case, and the whole organic matters are therefore stated together. + This number includes the albuminous compounds of the seed beans, which were not separately determined. Their proportion, however, could not have been large, and the error involved by adding them to the other organic matters of the entire produce is unimportant. analysis was therefore confined to the leaves and stems, the roots being separated at the point of junction. At this stage the leaves and stems were burned and analysed together, but the seed beans were examined separately, as it seemed probable that the composition of their ash, compared with that of the ripe produce, might show some interesting points of difference. The results were- These results, calculated after deduction of sand, carbonic acid, and charcoal, give From these analyses it appears that the total quantities of substances contained in the crop growing on an acre of land amounts to the following numbers in pounds avoirdupois: It is to be particularly noticed that the total quantity of ash here given does not correspond with that got by adding together the amounts given under the separate parts of the plants; and the reason for this is that the latter include the sand adhering mechanically to the surface, which is excluded from the former, as it is intended to embrace only those substances which really form a part of the tissues of the plant. The point most worthy of observation is the comparatively small quantity of mineral matter which the bean contains at this stage of its existence. It amounts, exclusive of roots, to only 10 lbs., and of this, less than one pound consists of phosphoric acid, and about two-thirds of a pound of potash. Lime, however, is comparatively abundant, amounting to 4 lbs., so that even at this period the bean has acquired the right to be distinguished as a lime plant. It is probable that at this early stage of its existence the bean has drawn little, if at all, on the resources of the soil, for the seed must have contained a sufficiency of mineral matters to supply most of that the produce contained. Unfortunately, I am not in a condition to offer any decided proof of this, from not having had an opportunity of analysing the beans used for seed, no sample of them having been preserved. We may, however, form an approximative estimate from the known composition of beans. A bean weighs on the average from nine to ten grains, so that the 100,000 beans which germinated must have weighed about 950,000 grains, or 130 lbs., and have contained about 4-5 lbs. of mineral matter, nearly half of which must have consisted of potash and a fourth of phosphoric acid. The produce, therefore, actually contains less of these particular elements than the seed did; and as far as they are concerned the plant may be said to have been independent of the soil. It is otherwise, however, with lime, of which the seeds could not have contained more than 1 or 1.5 lbs., so that a very large proportion of that contained in the produce must have been derived from the soil. And in this we find an illustration of that remarkable provision of nature, by which, whatever may be the nature of the constituents of the growing plant, potash and phosphoric acid are those most abundantly stored up in the seed, aud this is, no doubt, because these substances are intimately bound up with the first changes occurring in the germinating plant, while lime is of secondary importance, and not required, or, at least, not in large quantity, until the leaves and stems in which it is most abundant, begin to be developed. 2nd Stage, 1st July, 1864. During the month of June the plants made steady, but not rapid, progress, and by the 1st of July had attained an average height of 18 inches. The leaves, of course, had greatly increased |