128 



NATURE 



[November 23, 191 1 



foreign iiisoct fncmies and plant diseases whicli ar. lunv 

 levying an enormous annual tax, amounting to several 

 hundred million dollars, on the products of the farms and 

 orchards of the United States. 



In spite of the many pests which have already gained 

 foothold, and tnc control of which will be a permanent 

 annual charge on production, there remain many other 

 insect pests and plant diseases with equal capacity for 

 harm vvlnth, lurunateiy, have not yet come in; and it 

 is to protect from these new dangers that legislation is 

 now sought, not with the intention of prohibiting the trade 

 in imported stock, but to throw such safeguards around it 

 as will most protect both the importers and the sub- 

 sequent purchasers of such stock. 



The insect pests and plant diseases that have come in 

 are probably here for all time, but certainly no reason- 

 able objection can be made to the effort to safeguard the 

 future. The conscientious importer will be benefited, and 

 the home producers, the dealers, and all the great fruit 

 and forest interests will be protected by suitable inspection 

 and quarantine legislation. 



The San Jose scale had become established in Cali- 

 fornia on stock introduced from China about 1870, and 

 was known to be one of the most serious of orchard pests. 

 With proper supervision and quarantine it undoubtedly 

 could have been limited to the Pacific Coast indefinitely. 

 A quite unimportant importation of stock from California 

 by a proiiiiiieni .Missouri nurseryman in the early 'nineties 

 established this scale in several eastern nurseries, and this 

 led to the first concerted effort to obtain a national 

 quarantine and inspection law. The failure to reach an 

 agreement among the nurserymen, fruit-growers, and 

 entomologists as to suitable legislation prevented anything 

 coming from this effort, although several Bills were intro- 

 duci'fl I', ( <iiiiir< -'; fronj time to time. In the meantime, 

 the San Jos^ scale became so widely distributed by trans- 

 portation on nursery stock that quarantine against this 

 insect was no longer practicable ; and the United States is 

 now being taxed, and probably will be for all time, many 

 million dollars annually because there was no law under 

 which strong hold could have been taken of this danger 

 at the outset. 



As elsewhere noted, the recent effort to secure legislation 

 follovve<l thf entry and wide distribution in the United 

 States of brown-tail moth nests on nursery stock, chiefly 

 from northern France. The discovery about the same time 

 of thp fPtrv of the potato wart disease from Newfoundland, 

 and the white-pine blister rust, chiefly from one district in 

 Germany, greatly emphasised the immediate need for 

 Federal control. 



In the measure now before Congress, inspection of 

 imported nursery stock is left to the different States instead 

 of being undertaken by the Federal Government. A com- 

 plete system of notification is provided for, however, both 

 through the requirement of a permit and by subsequent 

 advices to be given by the customs offices, the broker or 

 first receiver of the stock, and the common carrier trans- 

 porting it. 



The first clause of the Bill is as follows : — It shall be 

 unlawful for any person, firm, or corporation to import or 

 offer for entry into ihe United States from any foreign 

 country any nursery stock unless and until a permit shall 

 have been issued therefor by the Secretary of Agriculture, 

 under such conditions and regulations as the said secre- 

 tary may prescribe, and unless such nursery stock shall be 

 accompanied by a certificate of inspection in manner and 

 form as required by the Secretary of Agriculture from the 

 proper official of the country from which the importation 

 is made to the effect that the stock has been inspected and 

 found free from injurious plant diseases and insect pests : 

 Provided, That this section shall not be construed as apply- 

 ing to plants or plant products solely intended for and 

 adapted to use as food, but to nurserv stock or other plants 

 or plant products for propagation : Provided further. That 

 nursery stock may be imported for experimental or scien- 

 tific purposes, without the certificate of inspection or the 

 permit of the Secretary of Agriculture hereinbefore re- 

 quired, upon su-th conditions and under such regulations 

 as the Secretary of Agriculture may prescribe : And pro- 

 vided further. That nursery stock imported from countries 

 where no official system of insoection for such stock is 



NO. 2195, VOL. 88] 



maintained, may be admitted upon such conditions 

 under such regulations as the Secretary of Agriculture 

 prescribe. 



One clause in the Bill malces provision for quarant 

 foreign districts or particular plant products in to. 

 districts to exclude diseases or insect enemies which 

 not otherwise be kept out. This is the provision •.. 

 has been most objected to by importing nurserymen, 

 especially by importers who have invested in fo 

 nursery enterprises in France. It is not the intentio 

 apply this section except in the case of diseases or ' 

 dangers which cannot be kept out by inspection or 

 infection ; in other words, at present it would apply 

 so far as is known, to the potato wart disease and 

 white-pine blister rust. Another clause provides 

 quarantining districts within the United States where 

 diseases or insect enemies have gained a foothold 

 such districts have been freed from such disease or in> 



PRACTICAL STANDARDS FOR ELECTRh 

 MEASUREMENT.' 



T^HE committee has to regret the death sinci 

 ■*■ meeting of the association of Dr. G. Johnstone Stoney, 

 F.R.S. He had been a member since 1861, and up to a 

 few years since continued his active interest in the u 

 In its earlier stages his skill in definition and his admi: 

 choice of nomenclature had proved invaluable to the 

 mittee. The collected reports which are to be issued si 

 will indicate how large a share in the establishme 

 the C.G.S. system of units is due to him. 



Republication of Reports. — The republication of thej 

 ports is not yet completed, but this should be done 

 the present year. The proofs of the reports from ij 

 1883 have been finally revised, and the remaining 

 will soon be ready. 



Lorenz Apparatus. — ^The progress made has been 

 factory. Preliminary experiments have shown that 

 apparatus is uninfluenced by changes in the earth's 

 netic field, and that the thermal E.M.F.s at the br 

 on the two discs very nearly balance. With the for 

 brush in use at present there are sudden changes 

 difference of the thermal E.M.F.s amounting to 2 Xj| 

 volt, and it may be difficult entirely to eliminate 

 With other forms of brushes, e.g. those made of gauze, 

 difference was often 1000 times as great. It was 

 difficulty which led Lord Rayleigh in 1883 to amalga 

 the edge of the disc, and as a further improvement 

 Viriamu Jones and Prof. .Ayrton used mercury jets ir 

 of brushes. Since in the present apparatus the change 

 only I in 10,000 of the difference of potential produe 

 one arrangement of the brushes and fewer for a 

 arrangement, it is hoped that mercury contacts will 

 necessary. Further experiments will be made in or 

 obtain greater perfection, if such is possible. 



Resistance Standards. — The construction of new mer - 

 standards of resistance in accordance with the specific 

 of the London Conference is being proceeded with, .nna 

 some of the standards will be completed this year. Similar 

 work is in progress in France, in Germany, in .Austria. '>"'' 

 in the United States. In the last-named country 

 standards have had all their constants determined, an^l 

 resistance unit so obtained is in very close agreement 

 that obtained from the old National Physical Labor, 

 standards. 



In the committee's report for 1908 it was shown that 

 many manganin resistance coils — some of which were pur- 

 chased by the committee in 1895 — ^'ere very changeable in 

 resistance, and in consequence frequent comparison wifti 

 mercury standards was necessary. In iqo8 it was ?' 

 at the Bure.iu of Standards, and confirmed at the Nat' 

 Physical Laboratory and at the Reichsanstalt, that ' 

 changes were largely due to the effect of moisture or 

 shellac covering the wire. To eliminate this source <■ 

 trouble many of the coils were hermetically sealed in 1909, 



1 RcD-rl prewnted a' t>ie PortsmnutH meet-nst of th^ British Asso ■ 

 hv the ComniU»<"f: on F.xperime ts for Improving the Con^ti-uct 

 P'artlcM <?tan''ar<t« for Flect'icil Meisurements. — Ixard Rayleigh ( 

 man), Pr. R. T. G'aiebrook (secretary). 



