Safety Lamps/American Safety Lamp A-H-G

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American Safety Lamp A-H-G.jpg - AMERICAN SAFETY LAMP ASHWORTH-HEPPLEWHITE-GRAY - Brass Ashworth-Hepplewhite-Gray safety lamp/gas tester, 9 5/8 in. tall to top of cap, 3 1/2 in. base dia., marked AMERICAN SAFETY LAMP & MINE SUPPLY CO. SCRANTON, PA., ex-Doc Kraft collection (The English Gray lamp of 1868 was one of the first lamps designed as a gas tester. In 1887 James Ashworth patented two improvements to the Gray lamp to control the air supply to the lamp. These included a rotating shutter on the cap and ferrules sliding over holes in the tubular pillars. This allowed feed air to be taken from the top of the lamp or from the base of the tubes. Other improvements included a gauze cylinder and a conical glass to throw light upwards to make roof inspections easier. This new improved Gray lamp would be known as the Ashworth Hepplewhite Gray (AHG) lamp. The AHG would become one of the best gas testers, being able to detect 2.5% firedamp. In use, hollow tubes direct feed air to enter the lamp through gauzed openings below the flame. A thin layer of gas against the mine roof can be detected without tilting the lamp by opening the cap shutter on top allowing air to be sampled and closing the tube ferrules on the bottom. In more normal operation, the cap shutter is closed and the tube ferrules are opened allowing air to be accessed to the flame. The lamp was in use from 1889 to 1920. The AHG lamp saw use in the United States as well and the lamp shown here was manufactured by the American Safety Lamp and Mine Supply Company of Scranton, PA. The US made lamps are identical in most details to the English AHG lamps. See Ballard and Van Fleet, Eureka #5, pp 20-24 and David Barrie, The Wand of Science)

American Safety Lamp A-H-G | AMERICAN SAFETY LAMP ASHWORTH-HEPPLEWHITE-GRAY - Brass Ashworth-Hepplewhite-Gray safety lamp/gas tester, 9 5/8 in. tall to top of cap, 3 1/2 in. base dia., marked AMERICAN SAFETY LAMP & MINE SUPPLY CO. SCRANTON, PA., ex-Doc Kraft collection (The English Gray lamp of 1868 was one of the first lamps designed as a gas tester. In 1887 James Ashworth patented two improvements to the Gray lamp to control the air supply to the lamp. These included a rotating shutter on the cap and ferrules sliding over holes in the tubular pillars. This allowed feed air to be taken from the top of the lamp or from the base of the tubes. Other improvements included a gauze cylinder and a conical glass to throw light upwards to make roof inspections easier. This new improved Gray lamp would be known as the Ashworth Hepplewhite Gray (AHG) lamp. The AHG would become one of the best gas testers, being able to detect 2.5% firedamp. In use, hollow tubes direct feed air to enter the lamp through gauzed openings below the flame. A thin layer of gas against the mine roof can be detected without tilting the lamp by opening the cap shutter on top allowing air to be sampled and closing the tube ferrules on the bottom. In more normal operation, the cap shutter is closed and the tube ferrules are opened allowing air to be accessed to the flame. The lamp was in use from 1889 to 1920. The AHG lamp saw use in the United States as well and the lamp shown here was manufactured by the American Safety Lamp and Mine Supply Company of Scranton, PA. The US made lamps are identical in most details to the English AHG lamps. See Ballard and Van Fleet, Eureka #5, pp 20-24 and David Barrie, The Wand of Science)

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