April 18, 1913] 



SCIENCE 



585 



for dispute are thereby removed. The 

 methods of testing with such apparatus 

 have been studied by the bureau and 

 sources of error in apparatus and methods 

 determined. As manufacturing methods 

 are developed and refinements in worlds 

 control are introduced, greater accuracy 

 in testing is required, and it is a great 

 advantage to the industries to have uni- 

 form and reliable instruments, standards 

 and methods. 



The same may be said respecting the 

 measurement of light and illumination. 

 The candlepower of a gas flame depends 

 upon the quality of the gas, the kind of 

 burner used, the height of the barometer, 

 the amount of moisture in the atmosphere 

 and the degree of purity of the air in 

 which it burns; hence, if the quality of 

 the gas is to be determined (in part) by 

 the candlepower given, it is necessary that 

 the test be made under very definite condi- 

 tions. The bureau has done considerable 

 work on flame standards employed in gas 

 testing, but much remains to be done in 

 this respect. Photometric standards are 

 supplied by the bureau for use in testing 

 electric lamps of various kinds and colors, 

 and gas standards are calibrated and cer- 

 tified. Thus, uniformity of value in light 

 measurement is secured for the whole 

 country, and indeed by means of interna- 

 tional comparisons made by the bureau for 

 the whole world, the international candle 

 being the name of the unit of light uni- 

 versally employed in this country. Calib- 

 rations are also made of photometers and 

 auxiliary apparatus. Similar uniformity, 

 together with a much higher degree of 

 precision, have been attained in electrical 

 measurements. Electrical energy is sold 

 by the kilowatt hour or the kilowatt year 

 (or a combination of the two) and a large 

 amount of testing is done by the companies 

 and commissions to insure accurate meas- 



urement of the energy delivered. Here 

 again uniformity and accuracy are pro- 

 moted by having a national laboratory for 

 calibrating and certifying standards and 

 instruments, and settling such disputes as 

 may arise from disagreeing measurements. 

 A large amount of work has been done by 

 the bureau to secure and maintain accurate 

 standards and instruments, but much re- 

 mains to be done, particularly with refer- 

 ence to the specifications of instruments 

 and apparatus and the improvement of 

 methods of measurement and testing. 



In addition to its work on instruments 

 and standards, the bureau has carried out 

 other investigations which have a bearing 

 on the work of the public-service commis- 

 sions. One of these is concerned with the 

 specifications of illuminating gas, and the 

 methods of testing to be employed in con- 

 trolling its quality. 



EEGULATION OF GAS COMPANIES 



Among public-service utilities, none has 

 been for so long a time and in so great 

 detail subject to legal requirements and 

 restrictions as the gas business. Such 

 regulation is of course intended to insure 

 good service. Many elements go to deter- 

 mine good or poor service, the principal 

 of which (chemical purity, heating value, 

 candlepower and condition as to pressure 

 of the gas) are enumerated and defined 

 more or less completely in many of the 

 gas ordinances now in force, together with 

 the tests that shall be made and the penal- 

 ties for failure to meet the requirements. 

 These ordinances are sometimes, therefore, 

 very technical and contain detailed specifi- 

 cations. In other cases the specifications 

 are very meager. In some cases old ordi- 

 nances long since out of date, so far as 

 their technical specifications are concerned, 

 are still in use; in other cases, old ordi- 

 nances have been extensively amended; in 



