be decreased, while the assimilable inorganic mat ters should be increased. Therefore a crop of beets should not be planted on a soil to which barn-yard manure has been recently applied. It is better to delay the sowing until the organic mat ter has been decomposed, and only the mineral matter remains, thus reducing the size of the beet but greatly increasing its percentage of sugar. Deherain's experiments, at Grignon, furnished results of a very similar character generally. In experiments , upon the exhalation of mois ture by plants in air and in carbonic acid, Mons. A. Barthelemy obtained results which led him to the conclusion that this action may be effected in three ways: 1. By insensible exhalation from the entire surface of the cuticle by a true gaseous dialysis. 2. By sudden emission of saturated gases which escape from the stomata when the plant is submitted to a rapid elevation of tempera ture, especially when inclosed. 3. By accidental exudation resulting from a defect in the equilib rium between the absorptive action of the roots and the work of the parts exposed to the atmos pherti in fixing carbon combined with the elements of water—work which ceases with the disappear ance of light. He believes that it is also right to conclude that heat exercises a strong influence upon this function, and that, at the equal tempera tures, carbonic acid, in the presence of light, has the effect of diminishing the evaporation. With regard to the exhalation of ozone by plants, Bel lucci has found that the air is not ozonized by coming in contact with the living plants or with parts of plants recently cut, but that the re-action previously supposed to be due to the action of ozone produoed in this way, is due to the action of free oxygen and light. The same test made with exclu sion of light, other conditions remaining the same, gives no re-Action. These facts support the opin ions resulting from the previous experiments of CliAz and Scoutetten, and are themselves sup ported by the experiments of Mr. Charles Kinzett, of England, who showed that ozone is not pro duced during the oxidation of essential. oils, hut that the re-action heretofore supposed to be due to ozone is, in such cases, due entirely to the influ ence of certain easily reducible organic com pounds of oxygen. The results of both the above investigators have been confirmed in a similar manner in our laboratory. Haberlandt, by a series of important experiments, has shown that the limits of the temperature of germination of agri cultural seeds vary from 3.8' Reaumer to 35° to 40° Reaumer, but that the most favorable tempera ture for germination seems to be from 13° to 20° Reaumer's thermometer. This thermometer has its zero at the freezing point, 32' Farenheit, and its boiling point at 80' or 212' of Farenheit. Frdm 40 ' to 130° Farenheit is the range of germinating power in seeds. The most favorable temperature ranging from about 60' to 90 '. Though these may be the limits under ordinary circumstances, 'Krausen has shown that if wheat-grain be thor oughly dried by gradual heating, and with the aid of chloride of calcium, it may then be heated to the temperature of boiling water without losing its germinating power. The presence of nitrate
of potash as a definite compound in plants, has been fully demonstrated by at least two investi gators during the past year. M. A. Boutin found in Araarecatits rake, in the dried condition, sixteen per cent., and in A. purpureus per cent. ; and he recommends the cultivation of these, as well as A. blitum, which he has previously shown to contain this compound, for the production of nitre. P. Gennadius has confirmed these state ments, having obtained crystals of potassic nitrate from A. albus as well as from Cannabis sativa, Lactitea sativa,Batata Lycopersicum, eseulen tum, Lappa major, and Artemesia absintkum. He has also demonstrated the presence of nitrous acid in a large number of other plants. We have also. to note the contributions made to our knowledge of the assimilation of nitrogen and ammonia by plants, and the formation of assimilable com pounds of nitrogen from the nitrogen of the atmos phere. Reasoning from the results of Deherain's experiments, we would conclude that the atmos pheric nitrogen used by the plant is supplied through the medium of the soil, where it is fixed by means of the hydrocarbons (such as humus) with the assistance of alkalies. This action is said to be favored by the absence of oxygen. Dehe rain's work has been more carried out by Armsby, under the direction of Prof. S. W. Johnson. The results of his experiments showed that the loss of nitrogen in the decomposition of nitrogenous organic matters in the compost heap could be very materially increased by the addition of caustic or carbonated alkalies. Vile states that in such decomposition thirty per cent. of the nitrogen present in the material is lost. Armsby finds that compost containing three and a quarter per cent. nitrogen, most of it in organic combina tion, lost eleven per cent. of the nitrogen in two months. Addition of gypsum reduced this loss to six per cent., but when potash was added to the extent of five per cent. there was no loss, but an actual gain of fifteen per cent. on the amount originally present. Prof. Johnson's experiments in this particular, with caustic lime, will doubt less give similar results. Contributions of an important character have also been made concern ing the absorption of ammonia by the aerial por tion of plants. That plants can absorb ammonia is fully established by the investigations of Schloesing and Mayer; but the latter investigator considers that we can have normal growth only when the ammonia is supplied to the roots, and that leguminous plants have not the special power to absorb and assimilate atmospheric nitrogen. Again Dr. Hellriegel, of Dolime, prosecuted an elaborate series of experiments, from the results_ of which it appears that ammonia-salts should not be applied to soils deficient in lime, for as. the ammonia is taken up by the plants'mineral acids are liberated, which have an injurious_ action on the roots. The subject will be found treated of further in the articles Germination, Geology, Maniires, Soils, and other subjects of a like character.