Apeil 18, 1913] 



SCIENCE 



587 



express opinions on technical questions of 

 great practical importance. 



A second investigation (already alluded 

 to) is in progress on the methods and in- 

 struments employed in testing gas for its 

 heating value, its candlepower and its 

 chemical purity, as well as in testing 

 meters and measuring gas pressures. This 

 will be embodied in a separate publication 

 which will be frequently revised and kept 

 up to date, in order to be as useful as pos- 

 sible to gas inspectors and engineers in 

 determining whether gas meets the specifi- 

 cations under which it is sold. 



A third investigation scarcely begun, 

 but which is much needed and deserves 

 extensive study, is on the safety and efiB- 

 ciency of gas appliances. Too many fatal 

 accidents result from defective gas appli- 

 ances, and the contamination of the atmos- 

 phere through imperfect combustion due 

 to defective appliances is a serious matter, 

 even when no fatalities result. This is a 

 question in which cooperation of all the 

 interests concerned can not fail to yield 

 important results. 



INVESTIGATIONS OF ELECTROLYSIS 



Another important investigation carried 

 out by the Bureau of Standards, which also 

 concerns public-utility companies, is the 

 damage by electrolysis produced by street 

 railway currents flowing through the 

 earth, upon gas and water pipes, lead- 

 covered cables belonging to telephone, tele- 

 graph and electric-light companies, and 

 the reinforced concrete foundations of 

 buildings and bridges. Such insulated 

 double conductor systems as those of New 

 Tork, Washington and Cincinnati provide 

 for the return of the current to the power 

 houses without flowing through the earth, 

 but most cities use the single overhead 

 trolley, and permit the current to return in 

 part through gas and water pipes and 



other underground conductors. Where the 

 current leaves such metal conductors, the 

 latter are corroded electrolytically, and in 

 some cases holes eaten through, thereby 

 interfering with the service and involving 

 expensive repairs. Many remedies have 

 been proposed, but as yet comparatively 

 little has been done to cure the evil. The 

 bureau undertook a thorough study of the 

 question for the purpose of testing some 

 of the proposed remedies and arriving at a 

 solution of the difficulty, if possible, that 

 could be applied generally. This investi- 

 gation is not yet completed, but already 

 valuable results have been reached and it 

 is hoped that shortly information will be 

 made available for the use of the street 

 railways that will permit them greatly to 

 reduce the volume of the currents flowing 

 through the earth without unreasonable 

 expense, and that will enable the public- 

 service commissions to deal more intelli- 

 gently with the question. The problem is 

 becoming each year more acute, since the 

 volume of electric current used is each 

 year increasing as the traffic increases, and 

 the damage produced is therefore increas- 

 ing at an increasing rate. Many lawsuits 

 have arisen because of this damage, and 

 such litigation is expensive because of the 

 large amount of conflicting expert testi- 

 mony adduced and the long time consumed 

 in the trials. Money expended intelli- 

 gently in solving the problem generally 

 yields better returns than money spent in 

 litigation. 



In England and some continental coun- 

 tries there have been rules on this subject 

 which have served as a guide to the electric 

 railways in building their roadways, and 

 hence they have been saved very largely 

 from the evil effects of electrolysis, al- 

 though at a somewhat increased first cost. 

 In this country the subject was neglected 

 for years. In the absence of public-service 



