On Night-Frosts and the Means of Preventing Their Ravages (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1893 edition. Excerpt: ...the situation of the thermometers. The torches were now placed in a somewhat different way. The whole field was surrounded by torches at a distance of 3 meters (5 steps) from each other and in the field itself, along the borders of the ditches, at a distance of 9 m (15 steps). The number of torches amounted to 250, or 125 torches to the hectare. The placing out of the torches was executed by two workmen in half an hour and the lighting took them another half-hour. The variations of the thermometers was very nearly the same as during the preceding experiments. In the field outside the shelterd area the temperature went down to-3,2 and the difference of average temperature to about 4. Considering that the thermometers were in a most unfavourable position to the torches, the average heating may unmistakably be estimated at 5. During the experiment a cold current of air from the southern side of the field was observed to descend from the sandhill and advance towards the trench. This current was particularly noticeable in the ditches, but could, for the moment, not be stopped, as the torches, in order to avoid the trampling down of the corn, were not placed across the plots of ground. At the end of the experiment, ice, or hoar-frost, had again been formed on the ears of corn the in surrounding field, but in the field of experiment there was not the least vestige of hoar-frost to be observed, not even on the low situated parts of it. On the lawn outside the sheltered field, the formation of hoar-frost began very early, and could even be traced, though in a small degree, in the middle of some open spots of the protected field which were not overgrown with rye. As at the preceding experiments, a cloud of smoke was drifting to and fro in the...