LATEST IN LAMPS

Hawke's Bay Herald-Tribune, Issue 179, 16 August 1937, Page 9

LATEST IN LAMPS

New Mercury Bulbs is Sensational ITS USE IN INDUSTRY i % — . f „ > 4 Development of a unique 100-watt mercury lamp, a relatively small tubular /'bulb yitlin a bulb". that is expeeted to aeeelerate lighting progress jfcaterially .and bring substantial benefita in 'commerce, iiuinduStry, and to tfich specialised fields as street lighting %nd plotogfaply, .. was announced reeentiy by. the Scientific American. Altlougl tle new lamp is still in tle experimental stagej laboratory experts were enthuSiasti# '.eAncernin g its potentialities. They.declined, lowever, to predict juBt.when tle double-bulb speciIflen would be mkdd commercially available. In its preient stage tle strange lamp produces 30 lumens per watt, or *bout as mucl light as tle standard flament 2 00 watt. lamp now emits. Early tests indicate tlat this experimental mercury lighting tool not only has a relatiVely 'long life, but maintains • remarkably high liglt output as well. About tle -size of a small cucumber — tle outer bulb has a diameter of 1* incli and an ell-over lengtl of less tlan six inches— tle new lamp is less tlan lalf as wide as tle standard 200-watt tupgsten filament lamp, and measures two incles less in lengtl. This compactness, plus otler efficiency advantages, experts explained, indicate that this bulb-in-bulb mercury lamp will, wlen perfected, adequately answer urgent needs for a mercury lamp, wlicl can be used satisfactorily in combination witl filament lamps to give a better quality of liglt from reasonably small lighting nnits. Tle outer bulb of tle new 100watt mercury lamp consists of * a tubular-slaped protecting envelope of solf glass. Tle iuner bulb, also tubular, but about the size of a stubby fat tlumb, is made of extra lard leatresisting glass. " This lollow glass "thumb" is only two inches long and about an inch in diameter. Witlin is a small amount of mercury and enougl argon gas to "star^* tle lamp. TJnlike tio xJfesent 250 and 400 watt murcury lamps, this bulb-in-bulb small edition operatos from either a 110-115 or 120 volt line without need of a voltage step-up for starting. A reactor or "choko" governing devic-c is, of course. required to keep thd lamp from "racing away witl itself" while in operation. Tt onerates at -about two atmospheres pressure. "Wlien the now lawTi ta first turnod on an are striltes. This emits a fceble bluish glow. The lnmn takes about flvp minutos to get fullv "warmed uo." Meanwliile, the crlow gradually builds up into an extremelv bn'Hmnt strpnm of livht. If nsM for steet l^htiTnr. f.hjs new lamp would rociuirc a .trapsformer to insure proper vnltage and c-urrent for flatisfactory operation.