December 4, 1885.] 



SCIENCE. 



497 



kind is indicated by any observations last night, 

 though a few of the meteor tracks (perhaps five or 

 six in all) vs^ould not pass strictly through the radiant 

 if traced back. C. A. Young. 



Princeton, N.J., Nov. 28. 



A bright meteor. 



On Friday, Nov. 13, about 10.30 a.m , the attention 

 of a number of our students vv^as attracted by a 

 brilliant meteor. 



The appearance as described by Mr. H. Toulmin, 

 of the senior class, is as follows : The path of the 

 meteor began 15° or 20° west and north of the zenith, 

 following a north-westerly direction, and ending some 

 20° from the horizon. 



The brightness he compares to that of Venus 

 when seen at night. The sun was shining brightly, 

 and no clouds were noticed. No explosion was heard, 

 nor did any fragments seem to reach the ground. 



C. L. DOOLITTLE. 



Lehigh university. 



Absorption of mercurial vapor by soils. 



Last year considerable attention was excited by 

 the proposition to utilize the insecticide properties of 

 mercurial vapor against the phylloxera or vine-louse. 

 This suggestion originated with Mr. J. A. Bauer, a 

 drusrgist of San Francisco, and himself the owner of 

 a vineyard in the infested region of the Napa valley, 

 where he had for some years experimented on the 

 efficacy of mercury, and satisfied himself of its use- 

 fulness as a preventive of infection, when, in plant- 

 ing, each cutting was surrounded by a few inches 

 of earth mixed with 'deadened' mercury. Upon 

 publication of the fact, a considerable demand for the 

 mercurial mixture (consisting of equal parts of finely 

 divided mercury and clay or chalk) was made by 

 persons interested, and many thousand vines were 

 treated in different localities in the manner prescribed 

 by Mr. Bauer. This was to mix thoroughly about a 

 peck of earth with an ounce of the above mixture, 

 and fill in with it the hole in which the cutting has 

 been placed, to the depth of at least six inches from 

 the surface. Many experiments were also made on 

 vines already infested, to see if the mercury would 

 gradually spread so as to disinfect the whole of the 

 root system. 



Contrary to expectation, most of these experiments 

 proved a failure, inasmuch as the phylloxera seemed 

 to continue, unchecked, on the roots already infested, 

 and in some cases clean cuttings bad become infested, 

 despite the surrounding mercurialized soil. 



Having witnessed a number of the successful ex- 

 periments upon which Mr. Bauer's recommendations 

 were based, I undertook an investigation of the cir- 

 cumstances of the reported failures, and soon discov- 

 ered two that were essential. One was that the mercury 

 used was considerably contaminated with lead, which 

 is known to diminish exceedingly the evaporation of 

 mercury ; another, that oil had been used in order to 

 facilitate the ' deadening ' process, and thus each 

 globule was covered with a film that additionally im- 

 peded volatilization. In fact, the iodine test for 

 mercurial vapor showed that a mere trace of the lat- 

 ter existed around the mixture furnished by Mr. 

 Bauer, while a similar one prepared with pure mercury 

 showed abundant volatilization at the ordinary tem- 

 perature, and acted very promptly upon insects. 



Yet, upon using the latter mixture in the manner 

 prescribed by Mr. Bauer, in a very clayey soil, neither 

 the insects nor the iodine test manifested the pres- 

 ence of mercurial vapor. It was now remembered 

 that Mr. Bauer's successful experiments had been 

 made in a very sandy soil of the city of San Fran- 

 cisco ; and the inference was plain, that, just as 

 aqueous vapor would be absorbed to a much greater 

 extent by a clay soil than by sand, so the mercurial 

 vapor was at first absorbed by the former until satu- 

 ration was reached, which might not be for many 

 weeks or even months ; the soil acting as an effectual 

 disinfectant until supersaturated. 



Experiments proved this surmise to be correct ; and 

 the investigation, still in progress, seems to show 

 that the capacity of soils for the absorption of aqueous 

 vapor may serve as an approximate measure of their 

 relative capacity for the absorption of mercurial 

 vapor also. Thus in pure sand, which in a saturated 

 atmosphere at 15° C. absorbed only .5 per cent of 

 aqueous vapor, the amount of mercurial vapor ab- 

 sorbed was too small for analytical determination ; 

 while in a clay soil, absorbing, under the same condi- 

 tions, 6 percent of watery vapor, the mercurial vapor 

 retained at 49° C. amounted to .012 per cent, equiva- 

 lent to about 130 grains per cubic foot of soil. Now, 

 since from one-fourth to one-half cubic foot was used 

 in the treatment of vines, it follows that from 33 to 

 65 grains of metal out of the 240 used in each case, 

 would have to evaporate and impregnate the soil, 

 before any free vapor would be available for action 

 on the insects. At the low temperature of the soil 

 this would naturally take a considerable length of 

 time : hence the failures. 



It is of course perfectly feasible to insure this im- 

 pregnation beforehand by exposing the mercurial- 

 ized soil to a higher temperature (e.g., to that of 

 49° C, easily attained in California by exposure to 

 the sun) for ten or twelve hours, or for a much 

 shorter time to steam-heat. A clay soil so prepared 

 will act on the phylloxera as promptly as when sand 

 is used ; all being dead, or incurably poisoned, within 

 from 20 to 30 hours. 



The method is therefore far from being a failure, 

 as has been industriously represented by interested 

 parties. It will accomplish all that has ever been 

 claimed for it ; to wit, the preservation of young 

 vineyards from infection through the ingress of the 

 phylloxera from above ; and, as there is no occasion 

 for disturbing the earth immediately surrounding the 

 stock of a vine, there is no reason why this protection 

 should not continue for all the time the vine is likely 

 to live. With proper precautions, it will also, no doubt, 

 be available against other insect pests of similar 

 habits ; e.g., the ' woolly aphis ' (Schizoneura lanicera 

 Hausm.). The conditions for successful application in 

 practice in various cases are still under investiga- 

 tion. E. W. HiLGARD. 



Agric. exper. station, Berkeley, Cal., 

 Nov. 23. 



The English sparrow. 



Your correspondent in Science, No. 147, asks for 

 information in regard to the English sparrows. In 

 this city (Cincinnati) and vicinity there are large 

 numbers of these birds, and local ornithologists have 

 no hesitation in saying they drive away the native 

 songsters. 



At my house, in one of the thinly populated suburbs, 



