74-i 



SCIENCB 



[N. S. Vol. XXVIII. No. 726 



France. — Professor Lippmann; il. E. 

 Benoit; 11. de Nerville. 



Germany. — ^Professor Warburg ; Professor 

 Jaeger; Professor Lindeck. 



Great Britain. — The Eight Hon. Lord Eay- 

 leigh (President) ; Professor J. J. Thomson ; 

 Sir John Gavey ; Dr. E. T. Glazehrook ; ilajor 

 W. A. J. O'Meara; Mr. A. P. Trotter. 



Guatemala. — Dr. Francisco de Arce. 



Hungary. — Joseph Vater; Dr. Desire Har- 

 sanyi. 



Italy. — Professor Antonio Editi. 



Japan. — ^Dr. Osuke Asano; Mr. Shigeru 

 Kondo. 



Mexico. — ^Don Alfonso Castello; Don Jose 

 llaria Perez. 



ISTetherlands. — ^Dr. H. Haga. 



Paraguay. — 11. llaximo Croskey. 



Eussia. — Dr. N. Engoroff, Col. L. Swentor- 

 zetzky. 



Spain. — Don Jose Maria Madariaga; Don 

 A. Montenegro. 



Switzerland. — ^Dr. Fr. Weber; Dr. Pierre 

 Chappuis; Dr. J. Landry. 



BRITISH COLO^^ES 



Australia. — Mr. Cecil W. Darley; Professor 

 Threlfall. 



Canada. — Mr. Ormond Higman. 



Crown Colonies. — Major P. Cardew. 



India. — Mr. M. G. Simpson. 



Secretaries. — Mr. M. J. Collins: Mr. W. 

 DuddeU: Mr. C. W. S. Crawley; Mr. F. E. 

 Smith. 



SCHEDULE B. — RESOLUTIONS 



I. The conference agrees that as heretofore 

 the magnitudes of the fundamental electric 

 units shall be determined on the electro- 

 magnetic system of measurement with refer- 

 ence to the centimeter as the unit of length, 

 the gram as the unit of mass and the second 

 as the unit of time. 



These fundamental units are (1) the ohm, 

 the unit of electric resistance which has the 

 value of 1,000,000,000 in terms of the centi- 

 meter and second; (2) the ampere, the imit of 

 electric current which has the value of one 

 tenth (0.1) in terms of the centimeter, gram 

 and second; (3) the volt, the imit of electro- 

 motive force which has the value 100,000,000 

 in terms of the centimeter, the gram and 

 the second; (4) the watt, the unit of power 

 which has the value of 10,000,000 in terms of 

 the centimeter, the gram and the second. 



n. As a system of units representing the 

 above and sufficiently near to them to be 



adopted for the pui-pose of electrical measure- 

 ments and as a basis for legislation, the con- 

 ference recommends the adoption of the in- 

 ternational ohm, the international ampere and 

 the international volt defined according to the 

 following definitions. 



III. The ohm is the first primary unit. 



IV. The international ohm is defined as the 

 resistance of a specified column of mercury. 



V. The international ohm is the resistance 

 offered to an unvarying electric current. by a 

 column of mercury at the temperature of melt- 

 ing ice, 14.4521 grams in mass, of a con- 

 stant cross-sectional area and of a length of 

 106.800 centimeters. 



To determine the resistance of a column of 

 mercury in terms of the international ohm, 

 the procedure to be followed shall be that set 

 out in specification I. attached to these reso- 

 lutions. 



VI. The ampere is the second primary unit. 



VU. The international ampere is the un- 

 varying electric current which, when passed 

 through a solution of nitrate of silver in 

 water, in accordance with the specification H. 

 attached to these resolutions, deposits silver 

 at the rate of 0.00111800 of a gram per 

 second. 



Vm. The international volt is the elec- 

 trical pressure which, when steadily applied to 

 a conductor whose resistance is one inter- 

 national ohm, will produce a current of one 

 international ampere. 



IX. The international watt is the energy 

 expended per second by an unvarying electric 

 current of one international ampere under an 

 electric pressure of one international volt. 



SPECIFICATION" I. — SPECIFICATION RELATDTG TO 

 MERCURY STANT)AEDS OF EESISTAKCE 



The glass tubes used for mercury standards 

 of resistance must be made of a glass such 

 that the dimensions may remain as constant 

 as possible. The tubes must be weE. annealed 

 and straight. The bore must be as nearly as 

 possible uniform and circular, and the area of 

 cross-section of the bore must be approxi- 

 mately one square millimeter. The mercury 

 must have a resistance of approximately one 

 ohm. 



