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422 Earth Inductor Compare Found Useful at Sea Marked advantages over the usual types of ships’ magnetic compasses are claimed for the earth inductor compass invented at the bureau of standards, de- partment of commerce. During a recent sea test it was found to be free from roll and pitch error to such an extent that it remained steady under con- ditions which caused the ship’s com- pass to oscillate 2 or 3 degrees. When a sudden change. of course was made the indicator moved freely and without oscillation, It has a further advantage that the parts affected by the ship’s magnetism can be placed in that part of the ship in which they will be least affected, up at the mast ‘head if desired. The in- 7 Rican Cer Develops Ne F:« complete and economical com- bustion of fuel, whether in sta- tionary or marine installations, a correct amount of air is essential. An insufficiency of air is the usual condi- tion which must be overcome and such a condition is not only uneconomical as far as combustion is concerned but ac- tually makes it impossible to develop the full amount of power for which the boil- er is designed. There are two ways of correcting this condition (1) by in- creasing natural draft by means of high stacks or chimneys and (2) by artificial means either forced or induced draft. Broadly speaking, the distinction be- tween forced and induced draft, is that between forcing air under and up through the grates, and in _ creating a partial vacuum in the uptakes leading to the stack by means of a blower at this point. Recognizing the importance of proper mechanical apparatus for supplying - air for combustion in boilers of marine in- stallations, since natural draft can not be increased to the necessary amount due to limitations in stack height, a great deal of experimentation and sev- eral workable systems have been devel- oped for forced and induced draft. One of the Jatest of these is the sys- tem developed by the German engineer, Professor Hans Haas, and recently in- troduced in the United States and Can- ada by the Th. Goldschmidt Corp., 15 William street, New York. In _ this system, the gases are forced up and out of the stack, thus increasing the air suc- tion in the furnace, accomplishing by artificial means much the same effect as that due to the provision of suitably high chimneys for _ stationary plants. MARINE REVIEW dicating instrument is unaffected by the ship’s magnetism and can be placed at any convenient point. The two parts are connected by ordinary wires. This compass is the invention of Dr. L. J. Briggs and Dr. Paul R. Heyl of the bureau of standards, and for its in- vention they were awarded the Magel- lan gold medal. It takes advantage of the fact that the voltage of a direct current dynamo is changed by changing the angle between the field and the brushes. In the compass, the earth’s magnetic field replaces the field magnet of the dynamo, and the brushes are mounted on the ship and turn with it. The armature is driven by a small, electric motor or may Be driven by a wind wheel. This type of compass has\ already been _ tried out, successfully in airplanes. F JA" xX 2 SSS ow fe S SS + 9 N SN Ne : Gi SiS “A % N a EEeTITIZIZZ a NS , ml oon 9 A ARBOR AAD 8 a SS LQG 72 ZILLA MMMM Z ZA A, Y, oe $ LL LILIA ATT LITT TERE IT ELIE K BN a7) i 4 T | S If TEKX' KY EXHAUST- KS Ree Aste uz {P SN ZN NING , Z Y Wham NYA MARK) DESCRIP Y, cad WA ae? yy Y $._|4- GUIDING BLADES. Y ae ) ” Alle) 5 estecrene YY Y, a 4. |\PEVOLUTION COUNTER SNe ae f | GALL BEARING rg ce) 4 E-_ | QL CONTHIN 5 he WITH FILTER ht La . ect RINGS. : S7ZAM A M a 7 Y. | TURBINE WHEEL K | SEAN LET. | 4. |Seao eaguq7voe. i. November, 1924 German Merchant Fleet Totals 1300 Ships At present the German merchant ma- rine totals 1300 vessels of 2,600,000 gross tons. The principal owners are: Ham- burg-American Line, 60 vessels of 335,779 gross tons; North German Lloyd, 37, of 274,139; Hugo Stinnes, 26, of 125,540:. Hansa Ling, 27, of 142,527; Roland Line, 43, of 99,872; Neptune Steamship Co., 55, of 35,626; Hamburg-South American Line, 17, of 129,447; Rhederei Aktien Gesell- schaft, 14, of 32,474; Kosmos Line, 14, of 70,013; Woermann Line, 10, of 44.419; German Australian Line, 17, of 86,042; German Levant Line, 24, of 45,789, and German East African, 6, of 41,024 tons, smaller companies make up the remainder of the fleet. “6 ian of Induced Draft Fick ~=ZFAN \ = GUIDE BLADES LLL LLLLLIE LP ISISSEELLSLSEL DED Es WL COOLER YN ome ‘—Wr > FIG. 1—CROSS SECTION THROUGH TURBU-DRAFYT APPARATUS, ALL PARTS IN- CLUDING THE TURBINE, OIL COOLER, GUIDE BLADES AND FAN BEING CON- TAINED IN ONE COMPACT SIMPLE MECHANISM OF MINIMUM SIZE