June 24, 1904.] 



SCIENCE. 



943 



For carrying on this work the laboratory 

 has been equipped with gas blast furnaces ; 

 electric furnaces which will maintain for 

 hours temperatures as high as 1,400° or 

 1,500° C, constant to within a few degrees; 

 electrically heated black bodies; and the 

 necessary accessory apparatus, such as po- 

 tentiometers, special resistance bridges, 

 recording pyrometers, etc. 



As primary standards for work in the 

 interval 600° C. to 1,600° C, thermo- 

 couples obtained from various sources are 

 used. These couples are referred to the 

 scale of the nitrogen gas thermometer by 

 measurement of their electromotive force 

 at known temperatures, viz., the melting 

 or freezing points of some of the metals. 



The high temperature scale used by this 

 bureau is based on the melting and freezing 

 points of the metals as determined by Hol- 

 born and Day in their painstaking re- 

 searches on the nitrogen gas thermometer. 

 The scale is thus a reproduction of the high 

 temperature scale used by the Physikalisch- 

 Technische Reichsanstalt, and its adoption 

 serves to extend the use of a uniform scale, 

 which is always to be desired in physical 

 measurements. 



The establishment of our standard scales 

 and the development of the apparatus re- 

 quired in testing have necessarily taken the 

 greater part of the time since the establish- 

 ment of the bureau. Research work has 

 not, however, been neglected. The estab- 

 lishment of the standard scales has opened 

 up a number of problems bearing on heat 

 and temperature measurements, the in- 

 vestigation of which Dr. Waidner and Dr. 

 Burgess have undertaken; this will form 

 an important division of the work. 



Section 3. Light and Optical Instru- 

 ments. — The work of this section, which is 

 under the personal charge of the director, 

 has only recently been inaugvirated, and 

 it can not be fully developed until the 

 second of the new buildings is occupied. 



Dr. Nutting is now carrying on some in- 

 vestigations on the electrical discharges in 

 gases, to determine among other things the 

 conditions necessary for producing a given 

 spectrum by such a light source. Mr. Bates 

 is making a careful study of polariscopic 

 measurements, with special reference to the 

 accurate determination of the percentage 

 of pure sugar in a sample. The bureau 

 has undertaken, at the request of the Treas- 

 ury Department, to supervise the work of 

 polariscopic analysis of sugar in all the 

 custom houses of the country, and this is 

 being done by Professor Noyes and Mr. 

 Bates. 



Section 4. Engineering Instruments. — 

 The work to be undertaken in the near 

 future in this section will include the test- 

 ing of gas meters, water meters and pres- 

 sure gauges, and testing the strength of 

 materials, using for the latter work a 

 100,000-poTand testing machine. Prepara- 

 tions for this work have only recently been 

 begun, but the work is progressing rapidly. 

 The range of the work will be extended 

 beyond that indicated above as fast as pos- 

 sible. 



DIVISION II. 



Section 1. Resistance and Electromotive 

 Force. — This work was begun by Dr. Wolff 

 in the office of standard weights and meas- 

 ures several years before the Bureau of 

 Standards was established. It was, there- 

 fore, the first section of the electrical work 

 to do testing for the public and is now in a 

 comparatively forward state of develop- 

 ment. In addition to standard resistances 

 and standard cells this laboratory also tests 

 precision resistance boxes, Wheatstone 

 bridges, potentiometers, precision shunts, 

 etc. Specific resistances, temperature co- 

 efficients and thermo-electric properties of 

 materials are also determined. A consid- 

 erable part of the work of this section con- 

 sists in the verification of apparatus of this 

 kind for the other sections of the bureau. 



