442 



SCIENCE. 



[Vol. I., No. 16. 



and 0.02 gold and silver. The bars are to be 

 of homogeneous metal, entirely soluble in aqua 

 regia, and of uniform densitj-. This density is 

 to be ascertained from two specimens taken 

 from the two ends of the bar. Before making 

 the alio}-, there shall be taken, from a mass of at 

 least 20 kilograms, two specimens of each 

 metal ; and the same shall be done with the alloy 

 before proceeding to make the bars or kilograms. 

 These specimens will then be sent to a member 

 of the international committee at Brussels, and 

 to a member of the French section at Paris, 

 respectivel}-, for independent analj'sis ; and the 

 work shall not proceed until these specimens 

 are examined and approved. The bars shall 

 present no defects which will not disappear in 

 the finishing ; and this finishing shall not be 

 undertaken until the rough bars have been sub- 

 mitted, examined, and accepted, provisionally, 

 bj' the French section. Messrs. Johnson, Mat- 

 they, & Co., are left free to use their own judg- 

 ment as to the best method of preparing the 

 pure metal, of making the alio}-, and of making 

 the bars. If any bars are rejected, they shall 

 be returned to the makers ; and the French 

 government shall not be held liable either for 

 the labor expiended or for the value of the 

 metal. 



Messrs. Johnson, Matthey, & Co., further 

 agree to furnish fort}" ingots of the same metal 

 for the construction of the international kilo- 

 grams. Each piece is to weigh between 1.150 

 and 1.200 kilograms, and to be subject to the 

 same conditions, regarding composition, alloy, 

 and density, as the bars. 



For this work the makers are to receive 2,000 

 francs per kilogram for the alloy accepted, 

 2,500 francs for work on each bar, and 150 

 francs for work on each kilogram. In part- 

 papBent, they are to take all unused alloj' at 

 the rate of 900 francs per kilogram, and the 

 sample specimens sent to Brussels and Paris 

 at the rate of 2,000 francs per kilogram. 



Before undertaking the adjustment of the in- 

 ternational standards, it was necessarj- to pre- 

 pare authentic copies of the original prototypes. 

 This delicate work was intrusted to two joint 

 committees, composed of members of the inter- 



national committee and of the French section, 

 one having charge of the comparisons of lengtli, 

 and the other of those of weight. The com- 

 parisons were successful!}' made. The copies 

 of the mUre des archives and of the kilo- 

 gramme des arcJdves are of platinum-iridium, 

 fulfilling all the 'conditions above mentioned, 

 as required for the new international standards. 



On the 26th of April, 1882, there was held a 

 meeting, at which were present the minister of 

 commerce, the director of the international 

 bureau, and five members of the international 

 committee and French section. After a state- 

 ment of the comparisons made, and results 

 obtained, the tj-pe-metre and type-kilogram 

 were, in the presence of the above-mentioned 

 parties, formally delivered into the hands of M. 

 Broch, the director of the international bureau, 

 who, from that moment, was charged with the 

 care, custody, and preservation, of these im- 

 portant articles. These types will serve as 

 the standards for the international metres and 

 kilograms ; and the limit of error allowable in 

 the marking and adjustment of the latter is fixed 

 at ±3 microns for the metre, and ±0.2 milli- 

 gram for the kilogram. 



To hasten as much as possible the final ad- 

 justment of the international standards, it is 

 ordered that the French section transmit each 

 metre and kilogram as it is ready, without 

 waiting for the preparation of the entire num- 

 ber. In this wa}- the comparison and verifica- 

 tion will be in execution by the international 

 committee, while the tracing of the metres, and 

 adjustment of the kilograms, are being done 

 bj' the French section. 



The construction and verification of the ther- 

 mometers which are to accompany the stand- 

 ards will be the care of the international 

 committee. 



During 1882 the personnel of the interna- 

 tional committee remained unchanged. The 

 committee will, however, soon suffer a loss in 

 the departure of one of its most able members, 

 M. Marek, who leaves to accept a position in 

 the Austrian bureau of weights and measures. 

 The resignation of M. Marek was accepted, 

 to take effect at the close of last j'ear ; but at 



