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Prevention of frost in orchards
814
J.J.
SMITH.
[J. F. I.
It is to be hoped that the generality of the method will induce others to work upon the theory of the principles involved along such lines as have been outlined. The attempt here has been to point out some of the fundamental ideas which seem to underly the work of Heaviside and to show wherein they differ from the ordinary mathematical conceptions. It has, however, been impossible to go into great detail. It would also appear from the results obtained that the determination of the Green's function is of fundamental importance in all such problems and that a collection of these functions, for various types of spaces, in easily accessible form, would be of considerable practical value. The point of view that the use of a does not prove equality as in ordinary mathematics, but only shows the degree of the convergence of one H-function to another, leads to interesting results in connection with the interpretation of generalized series, divergent series, fractional differentiation, etc., used by Heaviside. However, the results obtained in this connection are not very complete and cannot be gone into here on account of the already great length of this paper. In conclusion I wish to thank Dr. E. J. Berg for the many discussions on the points involved and for his never-failing interest during the course of the work.
Prevention of Frost in Orchards. (Clip Sheet, U. S. Department of Agriculture, No. 387, November 23, I925.)--A "windjammer " is the local name in California fruit-growing districts for a machine devised to raise the temperature of an orchard by the process of mixing the air during critical periods when the fruit is threatened by frost. Since the establishment of its fruit-frost service in 1917 , the Weather Bureau has had occasion to make practical tests with a number of these devices, but up to the present time has found no " windjammer " which can be recommended for complete protection from low temperatures. The use of many small orchard heaters is to-day the only practical means of raising the temperature of the air near the ground sufficiently to protect the fruit on the trees.
J.J.
SMITH.
[J. F. I.
It is to be hoped that the generality of the method will induce others to work upon the theory of the principles involved along such lines as have been outlined. The attempt here has been to point out some of the fundamental ideas which seem to underly the work of Heaviside and to show wherein they differ from the ordinary mathematical conceptions. It has, however, been impossible to go into great detail. It would also appear from the results obtained that the determination of the Green's function is of fundamental importance in all such problems and that a collection of these functions, for various types of spaces, in easily accessible form, would be of considerable practical value. The point of view that the use of a does not prove equality as in ordinary mathematics, but only shows the degree of the convergence of one H-function to another, leads to interesting results in connection with the interpretation of generalized series, divergent series, fractional differentiation, etc., used by Heaviside. However, the results obtained in this connection are not very complete and cannot be gone into here on account of the already great length of this paper. In conclusion I wish to thank Dr. E. J. Berg for the many discussions on the points involved and for his never-failing interest during the course of the work.
Prevention of Frost in Orchards. (Clip Sheet, U. S. Department of Agriculture, No. 387, November 23, I925.)--A "windjammer " is the local name in California fruit-growing districts for a machine devised to raise the temperature of an orchard by the process of mixing the air during critical periods when the fruit is threatened by frost. Since the establishment of its fruit-frost service in 1917 , the Weather Bureau has had occasion to make practical tests with a number of these devices, but up to the present time has found no " windjammer " which can be recommended for complete protection from low temperatures. The use of many small orchard heaters is to-day the only practical means of raising the temperature of the air near the ground sufficiently to protect the fruit on the trees.