Conservation. Glass gauges replacing steel. Markings on the handles of the new glass gauges, which replace steel gauges in the Frankford Arsenal, are produced by acid etching as shown on the attached labels. Glass gauges are lighter and cheaper than steel, permit greater visibility in inspection, are not as much affected by room temperatures and heat of operators' hands, are not corroded by perspiration, need no protection against rusting, do not acquire burrs that would change the effective sizes. They can save the annual use of 250 tons of critical tool steel in government arsenals alone