no substance soluble in water was added to the charcoal, it was moistened with 20 grammes of water, after having introduced the insoluble substances. The seed was planted in the charcoal, prepared as we have just described, after having undergone the commencement of germination in perfectly pure charcoal. The plants were watered with distilled water, and placed in the window of a room exposed to the sun, and of a southern aspect. The mineral substances were, moreover, prepared with much care; their purity was previously tested. The silicates of potassa and soda were prepared by dissolving with heat uncalcined silica in a concentrated alkaline ley. Phosphate of lime was obtained by double decomposition with nitrate of lime and phosphate of ammonia. The oxide of iron was obtained by precipitating the nitrate of sesquioxide of iron by succinate of ammonia and calcining the precipitate so as to obtain a mixture of sesquioxide and protoxide. We now briefly give the results of the experiments undertaken by the author : 1. No mineral substances, and no nitrogenous matters; plant extremely slight, weighing only 0.05 grammes after desiccation. 2. No mineral substances; the charcoal was moistened with a solution of 0.04 grammes of carbonate of ammonia in 20 grammes of water; the same solution was employed for watering the vegetable during the experiment. Plant very slight. Leaves green and longer than in the foregoing experiment. The stem, 7 inches high, bore a flower which did not fructify. The dried plant weighed 0.05 grammes. 3. No mineral substances: the charcoal was moistened with a solution of 0.1 gramme of carbonate of ammonia in 20 grammes of water. The plant died after shooting the first leaf. The solution of carbonate of ammonia was too concentrated. 4. No mineral substances: the charcoal was wetted with 20 grammes of water; then watered with a solution of 0.1 gramme of nitrate of ammonia in 20 grammes of water; 15 grammes of water was also added. The plant died after having put forth the second leaf. The roots were very short, and all turned towards the surface of the charcoal. 5. No ammoniacal matters. The following mineral matters were added to the charGrammes. coal: Silica } Silicate of Potassa { Potassa Carbonate of lime Phosphate of lime Sulphate of lime.. ..... Carbonate of magnesia 0.075 0.030 .... Grammes. 0.044 0.500 0.250 0.100 0.100 Dissolved in 20 grammes of water 0.030 0.030 Nitrate of potassa dissolved in 20 In this experiment less carbonate of ammonia was used, in order to compensate by this diminution for the quantity of nitrogen contained in the nitre. The plant grew to nine inches; it laid down, was very weak, and of a pale yellow color; the joints were enveloped by the sheaths of the leaves. A single flower was developed, which did not fructify. The dried plant weighed 0.37 gramme. 8. No potassa: mixture in the following proportions:Grammes. Hydrate of silica Carbonate of lime.. Carbonate of magnesia.. Phosphate of lime.. Sulphate of lime Nitrate of ammonia Nitrate of lime The plant died before the development of 0.050 the second leaf; a second seed was planted. 0.040 It was developed in a very feeble manner, 0.030 and without bearing flowers; it attained the 0.020 length of only 24 inches; its roots were Oxide of iron, containing manganese 0.020 long and extremely thin. 14. No sulphuric acid: the matters as in experiment 6, suppressing the sulphate of lime. Plant 11 inches long: leaves of a deep green, but short and narrow, and not so well developed as in the preceding experiment. Stalk normal, two flowers, no fruit; weight of the dried plant 0.12 gramme. The sulphur contained in the seed was not sufficient for the development of the plant. 15. Without sulphuric or phosphoric acid : mineral matters as in experiment 6, without phosphate and sulphate of lime, and with a supplement of 0.05 of nitrate of ammonia. Plant, 16 inches long, leaves of a deep green, stem regular, one lateral stem, two flowers without fruits. 16. Silica, potassa, and ammonia, in the following proportions : 0.070 Silica 0.080 Potassa 20 grammes } 0.020 0.040 Silicate of potassa dis solved in 20 grammes of water ...... 0.075 0.030 0.080 Nitrate of ammonia of water The plant died before the development of the second leaf. The roots were half an inch long, and turned upwards. 11. 0.5 grammes of carbonate of lime were added to the foregoing mixture, to see if the rapid perishing of the plant should be attributed to the absence of lime. In this new mixture the plant vegetated very well, as in experiment 6, although the color of the leaves was still very pale. Lime is, therefore, indispensable to the development of the plant. 12. No magnesia. Silica Silicate of potassa in 20 Potassa grammes of water Carbonate of lime .... Nitrate of ammonia dissolved in 20 grammes of water Sulphate of lime.. Nitrate of ammonia In 20 grms. 0.050 Nitrate of lime of water. 0.030 The plant attained the length of 13 inches, with a tendency to lie down; the first three leaves were very green, the following ones of a pale yellow. The dried plant weighed 0.32 gramme. 13. No phosphoric acid: the mineral matters as in No. 6, only suppressing the phosphate of lime. The plant attained the length of 16 inches: the leaves were of a deep green, but short and narrow; the stalk delicate but regular. Three flowers and a complete fruit; no lateral stalks; the dried plant weighed 0.17 gramme. The phosphoric acid contained in the seed appears to have replaced that which the soil could not furnish; only the development of the plant suffered in consequence. Plant, 15 inches long; leaves, pale; stem, abnormal and weak. Four flowers without fruit; weight of the dried plant, 0.21 gr. This experiment proves that the plant may flower without any magnesia in the soil, and that carbonate of lime may be replaced by other salts of lime. .... Plants extremely vigorous; leaves of a deep green; no dry spots; sheath of the last leaf less twisted than in the preceding experiment; last leaves of the lateral stalks 0.040 normal. 0.075 0.030 0 100 0.100 Nitrate of ammonia in 20 grammes 21. Less iron. Mineral matters in the same proportion as in the foregoing experiment, with the exception that only 0.010 grammes of oxide of iron was added. The plant was developed in a remarkable manner. Leaves green without dry spots; stem normal, and 24 inches long; joints rather weak; five flowers, but no fruits. Weight of the dry plant, 0·49 gr. 22. Soda and iron. Mixed in the same proportion as in experiment 20, only one-third of the alkali was soda. Plant very tender; leaves green, with dry spots; no flowers. 23. Iron and manganese. Mixed in the same proportion as in experiment 20, with the addition of 0.01 grs. of the carbonate of manganese. Plant vigorous; leaves of a deep green, without dried spots. Joints stronger than in experiment 21, but partially enveloped in sheaths. The sheath of the last leaf was turned round spirally, an irregularity which appears to have arisen from an excess of manganese. Length of the principal stem, 14 inches; several lateral stalks; no flowers. Weight of the dried plant, 1.09. 24. Iron and manganese. Silica Silicate of potash in 20 Potassa grammes of water } Carbonate of lime Principal stem 26 inches long; joints strong and free from sheaths. Fifteen flowers without fruit, weight of the dried plant 1.29 grammes. 25. Manganese without iron. Mixed in the proportion of experiment 20 without oxide of iron. Plant not very vigorous; leaves without spots, but pale; stem abnormal; 12 inches long; two tender flowers, without fruit, weight of the dried plant, 0.57 grammes. 26. Iron and manganese, without magnesia. Mixed as in the foregoing experiment : 0.1 gramme of oxide of iron was added. Stem and leaves less vigorous than in experiment 23; leaves of a deep green, without stains; stem abnormal. Length of the plant, 9 inches; no flower; one weak lateral stem. Weight of the dried plant, 0.36 grammes. 27. Iron, manganese, and soda, without potassa. In the foregoing mixture, 0.030 grammes of soda were substituted for the same quantity of potassa. Length of the stem, 15 inches; no flower; plant more tender than in experiment 23; the joints enveloped by sheaths. Leaves of a deep green, without stains; the last leaf was turned round several times on itself. Some weak lateral stalks were formed. Weight of the dried plant, 0.57 grammes. 28. The same mixture as in experiment 23; only the carbonate of manganese was not added until after the development of the fourth leaf, when stains began to appear. After this addition of carbonate of manganese the succeeding leaves were developed in a perfect manner; the stains were no longer exhibited, a result evidently due to the influence of manganese. In this experiment, the stem, which was very tender, attained the length of 14 inches; it bore three flowers, but no fruit. The leaves were of a deep green; the sheath of the last leaf was not twisted. The author attributes this result to the limited action of Grammes. the salt of manganese, which was applied 0.115 only on the surface. The contrary effect, 0.046 that is to say the twisting of the leaf, is pro0.500 duced by an excess of manganese. 0.100 29. Iron, manganese, potassa, and soda; 0.030 mixed in the following proportions { Nitrate of ammonia in 20 grammes of water 0.050 Grammes. 0.100 Carbonate of lime..... ....... 0.10 Leaves, stem, and joints, very vigorous and normally developed. The leaves were of a deep green; the sheath of the last leaf was not at all twisted. The cause of this vigorous development may be attributed CARBON ON WEEVIL.* either to the proportions of the mixtures, ON THE ACTION OF OXIDE OF somewhat modified, or to the simultaneous presence of potassa and soda. The author will endeavour to solve this question by new experiments. In this last experiment the plant attained the length of 29 inches; it bore fourteen flowers without fruit; its lateral stems were formed. The weight of the dried plant was 1.46 gr. The author, after having described his experiments, gives a series of conclusions, of which we subjoin a summary of the most important. From the first experiments, it results that, for a plant to be developed, it must find in the soil at once nitrogenous matters and certain mineral substances. If these mineral matters consist only of silica, phosphoric and sulphuric acids combined with potassa, lime, and magnesia, the plant vegetates more actively than it would do in a soil entirely free from mineral matters; however, the vegetation is very feeble, even in presence of ammoniacal salts, and to afford it full vigor, it is sufficient to add to the foregoing mixture a certain quantity of oxide of iron. An excess of iron was injurious by partially drying the leaves and preventing the formation of the flowers. The carbonate of manganese, added in small quantities to the oxide of iron, produces very useful effects. The utility of soda is not well demonstrated; however, it is certain that this alkali can be entirely substituted for potassa only to the detriment of the vegetation. In the same way magnesia cannot replace lime (Experiments 10 and 11). Among the acids, sulphuric and nitric are necessary to the regular development of the plant (Experiments 13 and 14); silicic acid is indispensable. To sum up, the fixed mineral matters absolutely necessary for the development of the vegetation of oats seem to be :Silica Phosphoric acid Sulphuric acid Potassa Lime Magnesia Iron, and Manganese. BY M. BARRUEL. THE weevil of corn, peas, &c, in the state of perfect insects, were plunged into impure oxide of carbon gas, arising from the action of sulphuric acid on oxalic acid. They died instantaneously; at least they appeared dead from their being completely motionless; but as insects submitted to the action of this gas return to life in fresh air, when the contact with oxide of carbon has not lasted long enough, I maintained its action for a certain time; after 48 hours, on putting them in contact with the air, I found them perfectly dead. state of larva might present a difference in Thinking that these same insects in the the impression which this gas might exert on them, I treated them in the same way; but the gas of this second experiment was mixed with a little air. Immobility was presented only after about 10 seconds. Some larvæ were, afterwards, added to the first. which permitted a portion of the gas to escape and give place to an equivalent volume of atmospheric air; they, however, became immovable in the same space of time. After 24 hours I put them in contact with the air; after two hours, those which had been last introduced into the flask returned to life; placed afterwards in the same circumstances as the first, they died. It is, therefore, easy, from these experiments, to destroy the weevil in both these states by their contact, for a certain time, with oxide of carbon, even impure; I intend to determine the minimum time necessary for causing their absolute death. I am now occupied with this. It was also important to determine whether or not the eggs of these insects resisted this action. To judge of this question, I took corn as healthy as possible, and I separated it into two parts; one was left in an open flask, with the corn containing the asphyxi * Comptes Rendus. ated weevil; the other was mixed in the same way with another portion of corn containing asphyxiated weevil, but in a flask containing oxide of carbon. If weevil be developed in the first, and not in the second, the question will be decided. From the results already obtained, I think that something useful has been done for the preservation of seeds which are rapidly destroyed by the enormous multiplication of these insects. It is not possible, for example, to transport habitually to the colonies barley in a natural state, but only in that of flour, which is heated and injured often, so as to be almost unfit for use after its passage through the tropics. If any experiments which I have not thought of should appear to the Academy desirlabe, I shall be very happy to follow its suggestions. I. THIS is a tabular report of an experiment made in Storr Park, Devon, to test the comparative efficacy of five different kinds of artificial manure in improving pond mud, the experiment being made on an acre of inferior pasture land, in the years 1847, 1848, and 1849. The land in which the experiment was conducted is of uniform quality, the soil being a light sandy loam, a few inches in depth, incumbent on a stratum of white clay. The land underwent thorough draining in 1844, prior to which it would not produce more than 5s. per acre. No manures were applied in 1848 and 1849. The object of extending the experiment over three years was to test the durability of the different manures. |