IGG 



SCIENCE. 



[N. S. Vol. XXI. Xo. 527. 



pence, to say nothing of guineas, crowns 

 and farthings with their odd ratios, being 

 cumbersome in comparison. But our 

 weights and measures are far more cum- 

 bersome and complicated than the English 

 coinage. We weigh most merchandise by 

 avoirdupois weight, gold and silver by troy 

 weight, medicines by apothecaries' weight, 

 diamonds by diamond carat weight. We 

 have dry quarts and liquid quarts, long 

 tons and short tons, and a hundredweight 

 is not 100, but 112 pounds. Coal is usually 

 purchased at wholesale by the long ton and 

 retailed by the short ton. A bushel some- 

 times means 2,150.4 cubic inches and some- 

 times it means a certain number of pounds 

 weight of a commodity. The American 

 bushel is derived from the old English 

 Winchester bushel, but the legal English 

 bushel of the present day is larger by 69 

 cubic inches. On the contrary, the Eng- 

 lish gallon is much larger than the Amer- 

 ican gallon, the difference amounting to 

 about 20 per cent. We measure wood by 

 the cord, stone by the perch, earth by the 

 cubic yard. Moreover, among the dif¥erent 

 states of the union are considerable differ- 

 ences in custom and in legal equivalents. 

 We are, of course, much better off than the 

 countries of Europe were a century ago, 

 but the difference is all too small. 



Our medieval system of weights and 

 measures is, however, too deeply rooted to 

 be easily displaced. But the metric system 

 is being used in this country more than is 

 generally realized and our rapidly grow- 

 ing foreign trade is bringing it more than 

 ever to the attention of merchants and 

 manufacturers. In England a strong ef- 

 fort is being made to adopt the metric 

 system, with the hope that ultimately a 

 decimal system of currency may also be 

 adopted. The English colonies are even 

 jrioro progressive than the mother country, 

 and strong influences are at work to secure 

 the decimal systeiri throughout the British 



empire. It will be greatly to the advan- 

 tage of the United States to keep abreast 

 of this movement^ and not to be the last 

 among the civilized nations of the world 

 to throw off the incubus of an incoherent 

 system of weights and measures, whose 

 chief claim lies in the fact that it is in 

 general use. 



The testing of lengths and masses con- 

 stitutes one of the most important branches 

 of the work of the bureau. As I have said, 

 this work has been done by the government 

 for many years, hut the facilities for the 

 work are being immensely improved by 

 the bureau so as to extend the range and 

 increase the accuracy of the work. The 

 new laboratories will contain many new 

 balances and comparators and every pre- 

 caution is being taken to secure the most 

 favorable conditions possible for precision 

 work. When the installation is completed 

 it will probably be the best of the kind in 

 the world. 



I have said that the three fundamental 

 units of measure are those of length, mass 

 and time, or the meter, kilogram and sec- 

 ond. From these are systematically de- 

 rived various other units, all forming what 

 is often called the centimeter-gram-second 

 system, or, more briefly, the c.g.s. system. 

 It is not my purpose to enumerate the vari- 

 ous derived units which are employed in 

 scientifie and technical work, but rather to 

 describe briefly some of those employed in 

 the testing and research work of the bu- 

 reau. And first let me speak of the work 

 in heat and thermometry. The testing of 

 thermometers is one of the most important 

 branches of the work of the bureau. This 

 work is under the charge of Dr. Chas. W. 

 AVaidner, who is personally known to some 

 of you. Dr. Waidner and his assistants 

 have devoted a great deal of effort to the 

 acquisition of reliable standard thermom- 

 eters and to the investigation of instni- 

 iiieiits and methods. In this they have 



