in 430 hours at a temperature which was between 37° and 42°, averaging above 40° F., while the Waushakum variety required 460 hours at the same temperature.

Sturtevant calculates the sum total of temperatures by three methods, a comparison of which is instructive. His results are in the following table:

Thermal constants for maize at Geneva, N. Y., from germination to blooming.

The dates were: Corn planted May 16, 1883, and May 19, 1884; sprouted May 28, 1883, and May 26, 1884; bloomed July 16 to August 8, 1883, and July 16 to August 26, 1884.

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Thermal constants for peas from sprouting to maturity at Geneva, N. Y.

Peas planted April 21 and May 12, 1883; April 28, 1884; ripened July 10 to August 6, 1883; July 2 to 28, 1884.

These figures show eccentricities from year to year in the same variety, but the peculiarities of the varieties are much larger than these eccentricities. Sturtevant suggests that actinism has an influence scarcely second to temperature.

SORGHUM.

UNITED STATES.

W. E. Stone (Agr. Sci., Vol. IV, p. 166) summarizes the results of the experiments on sorghum published by Wiley in Bulletins Nos. 20 and 26, Division of Chemistry, United States Department of Agriculture. He says the controlling conditions of success are suitable soil and climate, proximity of cane fields to the factory, supply of water and fuel, cost of the factory, and careful control of its operations. All experience points to southern central Kansas as the region best adapted to the growth of the sorghum. In New Jersey the plant, which at one time gave hopeful results, has deteriorated until it has become a worthless variety for sugar making, or even for the production of sirup. In Louisiana the results were disappointing in seasons which were the most favorable for the sugar cane. At Conway Springs, Kans., the average percentage of cane sugar was 12.42 in 1888 and 11.98 in 1889, being the best record of all.

In general, with a normal amount of moisture, and other things being equal, the percentage of sugar depends upon the amount of sunshine received; excessive moisture is detrimental, as it directly interferes with nutrition and indirectly as being accompanied by cloudiness.

A mean temperature of 70° F. is the minimum necessary to mature early varieties. The semiarid region south of the isotherm of 70° F. in the southwest central portion of the United States is best adapted to the growth of sorghum. East of the Mississippi the recurrence of wet seasons renders the crop uncertain. A permanently improved plant can certainly be developed from existing varieties by selection.

OATS.

KANSAS.

During the drought of 1890 the Kansas Agricultural Experiment Station secured the following comparative observations: On unplowed land the yield of listed oats was 2.4 bushels per acre better than on plowed land; the yield of drilled oats was 1 bushel per acre better on unplowed land; the yield of oats cultivated into the soil was 5 bushels per acre better on the unplowed land; the oats sown broadcast on plowed land gave the same results as the oats cultivated into unplowed land; the oats plowed under gave the least harvest of

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all the five methods of seeding, while the drilled oats gave the best. This superiority of the drilled oats is probably due to the fact that the instrument pressing firmly upon the soil makes a firm bed at the bottom of the drill, into which the seed is dropped. In a loose soil oats run to straw, but in a firm soil they give a larger percentage of grain. In the present case oats drilled into unplowed land gave 34.5 bushels per acre, but when plowed under gave 21.6 bushels, or a loss of 35 per cent.

As to the time of harvesting oats, they should be cut early, viz, in the dough stage, if the straw is wanted for feed; but if the grain alone is wanted they should be allowed to mature, notwithstanding the fact that there is then a greater loss due to the beating out or dropping of the grain in harvesting. (Agr. Dept. Exp. Sta. Record, Vol. II, p. 222.)

OHIO.

In Bulletin No. 3 of Volume III of the Ohio Agricultural Experiment Station it is shown that the experiments of 1889 indicate that more cultivation should be given in dry seasons than in wet seasons.

FREEZING OF PLANTS AND SEEDS.

Detmer (1887), with reference to the effect of low temperatures on plants, finds:

(1) Fruits and seeds that have been dried in the air can be exposed for a long time without injury to very low temperatures, but if they have first been swollen with moisture they are destroyed by low temperatures. In the case of wheat exposed to a temperature of -10° C., although it will germinate, still its power of growth is decidedly less than before.

(2) Many plants and parts of plants withstand temperatures below freezing, and many bacteria withstand much lower temperatures; those experimented on by him were not killed by an exposure to temperatures of-17° C.

(3) In accordance with Sach's experiments, he finds many plants which after being frozen survive if they are thawed out in water at low temperatures (6° C.), but not when thawed out in water at +17° C., thus showing the manner in which a warm rain may act injuriously upon a forest.

(4) Certain plants are definitely destroyed by freezing independently of the subsequent thawing, such as the leaves of the begonia.

(5) Experiments have given a negative result as to the question whether any plant, although accustomed to the warmest climate, can be killed by a short exposure to a low temperature which is, however, still above freezing. (See Wollny, X, p. 236.)

WHEAT.

A detailed study of the relation of low temperatures to the growing of wheat has been made by S. G. Wright, of Indiana, from which I take the following conclusions:

Sleet. When the winter wheat has its blades covered with ice that has fallen as sleet, and after the ice has melted off a microscopic examination shows the cellular structure to be altered, the epidermis is separated from the underlying cells and there is a general disunion of the cells, and when the growing season comes the plants are found to be entirely dead.

Sudden thawing.-Wheat plants exposed to a very low freezing temperature in dry air if thawed out slowly are not much injured, but if thawed out rapidly the younger sprouts are completely killed and the older ones subsequently die. The similar rule obtains for the germination of seeds. When frozen seeds were quickly thawed out only 18 per cent germinated, but when slowly thawed out 86 per cent germinated.

Freezing temperature of the juices of the wheat.-The juice extracted by pressure from the wheat has a lower freezing point than that of pure water when contained in its original living tissues, but after being extracted by pressure it freezes at an intermediate point below that of pure water. Again, the juice extracted from plants that have been exposed to a low winter temperature withstands freezing better than the juice from plants that have not had such exposure. For example, the juice within the cells was not frozen at -13° C., while that thrust out of the cells froze at -6° C., and in general the power to resist freezing is increased by exposing plants to the ordinary winter temperatures of the open air.

Method of sowing. The best method of sowing wheat in order that it may withstand severe winter weather is (1) to avoid mulching or having any layer of porous material about the roots of the wheat, as experiment shows that this is a decided injury both to the wintering, the after growth, and the harvest. An average depth of seed planting of 1.5 inches is much better than three-fourths inch or 3 inches.

Range of temperature for germination.—According to Sachs, the minimum temperature is 5° C. and the maximum 37° or 38° C. According to Haberlandt, the temperature for germination ranges between 0° and -4.8° C. at the lower limit and 31° to 37° C. at the upper limit. Wright's experiments, at a constant temperature of 39° C., gave germination successful in forty-eight hours; at a temperature of 42.5° C. only a very few seeds could be made to germinate. At a temperature of 0° C. the seeds germinated in ten days; hence the extreme range of germinating temperatures for winter wheat of the varieties thus tested in Indiana is from 0° to 42.5° C. As to the effect

on germination of freezing the seeds just before they were ready to germinate, it was found that seeds soaked until ready to germinate and then kept frozen for a length of time required a longer time to complete the germination than did those that had not been frozen; the retardation increased in proportion to the duration of the freezing, amounting to about twelve days for a freezing of twenty-four days. The percentage of thawed-out seeds that germinated was also smaller in proportion as the duration of the freezing increased, being 44 per cent for a duration of twenty-four days.

Changes in the seeds produced by frost.-After the seeds had remained frozen for ten to twelve days a white, glutinous material oozed out at every slight break in the coat of the seed. A microscopic examination showed that the cell wall and starchy protoplasm was almost entirely disorganized, but the starch granules themselves were entirely unaffected. Strange to say, the power of the seeds to germinate was not destroyed by this. (Agr. Sci., Vol. IV, p. 337.) Protection from frosts.-The formation of artificial clouds of smoke for the protection of plants from frost is generally successful, and should be resorted to in critical cases; thus, in a vineyard at Pagny about 3 a. m. of May 13, 1887, when the temperature was 3° F. below freezing, liquid tar was ignited, which had been poured into tin boxes, as also pieces of solid tar. Large clouds of smoke quickly enveloped the vineyard; the fires lasted for about two hours, but the smoke lasted considerably longer. All injury to the plants by frost was entirely prevented. (Agr. Sci., Vol. I, p. 172.)

INJURIES AND BENEFITS DUE TO WIND-BREAKS.

Protection against the injurious effects of wind may be obtained by the use of wind-breaks, which are usually made by planting a couple of rows of trees on the windward side of the field, or by so arranging the plantation that the hardiest and most vigorous deciduous trees are on the windward side. According to Bulletin No. IX issued by the Cornell University Agricultural Experiment Station, the benefits derived from wind-breaks are the following: Protection from cold, diminution of evaporation from soil and plants, diminution of the number of windfalls, diminution of liability to mechanical injury to trees, retention of snow and leaves, facilitation of outdoor labor, protection of blossoms from severe winds, protection of trees from deformity of shape, diminution of evaporation and drying up of small fruits, diminution of the encroachment of sand or the loss of dry soil or the scattering of rubbish, increased rapidity of maturity of fruits, and encouragement of birds that are beneficial to agriculture.

Among the organisms arrested by wind-breaks and usually reckoned as an injurious climatic influence are the fungi or the spores of fungi.