MISCELLANY. 



629 



firmation of his theory in the drowsiness 

 which settles down on elderly men over 

 their wine. " Nature says to them, ' Go to 

 bed.' They will not go to bed, but still 

 Nature will not allow her law to be broken, 

 so she sends them to sleep sitting in their 

 chairs." But, then, does not Nature quite 

 as clearly indicate, by means of the night- 

 mares and the unrest with which she tor- 

 ments the would-be sleeper who has gone 

 to bed directly after a heavy meal, that a 

 full stomach is not the best preparation for 

 slumber ? Many persons with whom this 

 prescription for sleep would fail, may per- 

 haps find another prescription given by Mr. 

 Buckland more effectual, viz., eating onions, 

 the essential oil of which possesses highly- 

 soporific powers. 



The Use of Paris-Green. The use of 



Paris-green in deaUng with the Colorado 

 beetle has been condemned on the ground 

 both that it poisons the soil, rendering it 

 sterile, and that it is liable to be absorbed 

 by the plant. Certain experiments made by 

 Mr. McMurtrie, chemist of the Department 

 of Agriculture, throw much light upon this 

 question, and therefore are worthy of repro- 

 duction here. To determine the first point, 

 that is, whether the Paris-green poisons the 

 soil, Mr. McMurtrie planted peas in a num- 

 ber of flower-pots, each containing the same 

 amount of earth, and all but one containing 

 a certain proportion of Paris-green. The 

 proportion of this substance varied from 

 100 milligrammes up to five grammes. The 

 first five pots contained Paris-green as fol- 

 lows : No. 1, none ; No. 2, 100 milligr. ; 

 No. 3, 200 ; No. 4, 300 ; No. 5, 400. In all 

 of these the peas grew equally. In No. 6, 

 containing 500 milligrammes, the plant was 

 less vigorous than in No. 5. This, then, 

 may be regarded as the proportion of Paris- 

 gr'een which impairs the fertility of soil. As 

 the proportion increases, the plant grows 

 feebler and feebler till No. 12 is reached, 

 containing two grammes of Paris-green. 

 Here the plant barely appears above the 

 surface. In the rest of the pots, containing 

 respectively three, four, and five grammes, 

 the plant sends no shoot above the surface. 

 The proportion of 500 milligrammes in the 

 flower-pot No. 6 is equal to 145.6 grammes 

 per cubic foot, or 906.4 pounds per acre, I 



calculating for a depth of one foot. Now, 

 as less than two lbs. of Paris-green per 

 acre is enough to use in warring against 

 the beetle, it would take about 500 years 

 to poison the soil, supposing the green to 

 be applied every year, and that it was all 

 retained. "But when rotation of crops is 

 practised," says Mr. McMurtrie, " and appli- 

 cation of the poison cannot therefore take 

 place upon the same plot more than once in 

 three or four years, it is probable that each 

 application, being acted on by the natural 

 solvents of the soil, will be removed by 

 drainage before another is made." To the 

 question whether arsenic can be absorbed 

 and assimilated by the plant in the economy 

 of growth, he replies in the negative. All 

 of the plants grown, from the largest to 

 the smallest, were examined according to 

 Marsh's test for arsenic, but its presence 

 could not be detected. 



Periodicity of Thunder-storms. W. von 

 Bezold lately presented to the Munich Acad- 

 emy of Science a paper on the " Periodicity 

 of Thunder-storms," basing his remarks up- 

 on a series of observations which extended 

 over a period of 105 years prior to 1869. A 

 synopsis of this paper we here reproduce 

 from the American Journal of Science. He 

 finds that in years when the temperature is 

 high and the sun's surface relatively free 

 from spots, thunder-storms are abundant. 

 But as the maxima of the sun-spots coin- 

 cide with the greatest intensity of auroral 

 displays, it follows that both groups of phe- 

 nomena, thunder-storms and auroras, to a 

 certain extent supplement each other, so 

 that years of frequent storms correspond to 

 these auroras, and vice versa. He observes 

 that such a connection between sun-spots 

 and storms does not by any means sanction 

 the supposition of a direct electrical inter- 

 action between the earth and the sun, but 

 may be simply a consequence of a degree 

 of insolation dependent upon the sun-spots. 



These changes in the insolation, accord- 

 ing to Koppen, manifest themselves in dif- 

 ferent latitudes not contemporaneously but 

 successively. The phenomena of thunder- 

 storms, on the other hand, do not depend 

 alone upon the condition of the place in 

 question with respect to temperature, but 

 also on the condition of the atmosphere at 



