The Birmingham age-herald., 1922-08-27
HUGE TUBE MAY
 THROW THE VOICE
 ACROSS ATLANTIC
Most Powerful Vacuum Tube in World, Developed by Bell Laboratories, to Deliver
 100 KiIoWatts
By JACK BINNs

The most powerful vacuum tube fully produced in the Bell labora- tories with an output of 100 kilo- watts. This remarkable instrument, which Is the continuation of an ex- tended period of research work, Is expected to completely revolution ize long distance wireless telegraph communication and may also make transatlantic radio telephony pos sible within a very short time
 There is not the slightest doubt but that it places this country in the most strategic position in the race to be the first to throw the voice across the broad expanse of the Atlantic.
 Although the new tube can be conveniently held in one hand it will produce sufficient power to bridge the ocean for telegraphic purposes and will in time completely replace the cumbersome and ponderous ma chinery which is now necessary for that purpose. Moreover, the cost of maintaining transatlantic ser vice with such tubes will be almost infinitesimaI as compared with the machinery.
 Transatlantic Telephony
 Tn my opinion two such tubes connected in parallel will undoubted- ly carry the voice across the ocean, while four of them will unques- tionably do so under practically all conditions that may exist so that reliable uninterrupted service coulo be maintained between New fork and London.
 nf n big tubes there lies a story of steady progress in overcoming physical ob- stacles, and as a consequence the tube in its final form departs radi- cally from all existing types. The success attained with 1t is due 10 two outstanding features-first, the system of water cooling, and sec ond, the process whereby large pieces of metal have been sealeo into glass in such a manner that the vacuum can be maintained unoer wide ranges of temperature.
 The tube differs from the standard form In that the plate Is on the out side of the tube, so that 1t can pc placed in a socket where water IS circulating, and thus take care or the cooling of the tube during the perloo of operation.
 The original work on the develop ment of the high-power tubes In the Bell laboratories at the western Electric company was unoer ertaN1n ?, by Dr. E. R. Stoekle and pr. U, E' Buckley, and the water cooling sys- tenn was devised by the former
 Ten-Kilowatt Tube Built
 At the conclusion of the war steps were taken to continue the work by construction of 10-kilowatt tuoe. The story of this early work Is told by W. Wilson in the following words:
 "Mr. W. G. Housekeeper and Dr. M. J. Kelly undertook the further improvement of the water-cooled tube. the former assuming the task of developing the mechanical struc- ture. and the latter that of deter mining the electrical design and the process of tube exhaust.
 "Mr. Housekeeper adopted into the construction of the tube remark able type of vacuum seal which he had previously developed. These seals are made between glass and metal and can be made In any de- sired size. They are capable oi withstanding repeated heating ana cooling over wide ranges of tenn perature, from that of liquid air 10 $50 degrees c, without cracking ana without impairment of their vacuum holding properties.
 ''It is no exaggeration to say that the invention of these seals has made possible the construction of vacu- um tubes capable of handling Tn single units powers of any magni- l. tude which may be called Tor m wireless telegraph and teiephone transmission
 Seal Withstands Stress
 "The underlying principle com nected with the making of this seal consists in obtaining an intimate connection between the glass and metal, either by chemical combina- tion or by mere wetting, and in SC proportioning the glass and metal portions of the seal that the stresses produced when the seal Is heated ol cooled will not be great enough te rupture either the glass or the june tion between the glass and metal.
 "The three principal types Of seals developed by MT. Housekeeper ar' known as the ribbon seal, the disk seal and the tube seal.
 If a copper ribbon is directl, sealed through glass it Is found tha the glass and copper adhere alonf the flat faces of the seal. but tha ruptures occur along the edges. Thi! Is due to the fact that as .he sea cools after being made the glass 1T contact with metal Is capable of re sisting tha shearing and tensil,