January 10, 1902.] 



SCIENCE. 



69 



tage of sucli movenieiits where strata move 

 in proximity witli differing motions. Langley 

 has shown the possibility of taking advantage 

 of the gustiness of the wind when soaring. At- 

 tention is called to the fact that the horizontal 

 motion of an aeroplane greatly increases the 

 pressure beneath it when falling, tending thus 

 to sustain it effectively. On this fact de- 

 pends the possibility of flight. The sustain- 

 ing pressure is also reinforced by an impor- 

 tant complementary suction above, with sim- 

 ilar effect in supporting the falling mass. 

 Artificial flight is a question of speed of hori- 

 zontal motion ; no man can raise himself from 

 the ground by any mechanism operated by 

 muscular power except with preliminary accel- 

 eration in the horizontal direction. Lord 

 Eayleigh is inclined to agree with Sir Hirani 

 Maxim that the problem of artiflcial flight is 

 mainly one of time and money. It would pre- 

 sumably be mainly a military problem. He 

 does not think it will prove a safe method of 

 conveyance; but, as Maxim has remarked, -we 

 have not even yet succeeded in making war 

 quite safe. 



The Hon. Charles A. Parsons, in the second 

 paper, discusses motive power and the steam 

 turbine. He commences with a paraphrase of 

 a page in the introductory section of Thurs- 

 ton's 'History of the Steam Engine,' in which 

 the account of the steam turbine in Hero's 

 'Spiritalia' is presented, and goes on to say 

 that an experiment made years ago in the 

 production of a redesigned Hero engine en- 

 abled him to obtain twenty horse-power on a 

 consumption of but forty pounds of steam per 

 horse-power-hour, which is a very fair per- 

 formance for engines of the simpler modern 

 forms and of similar power. A later model 

 illustrated his system of compounding, but 

 without commensurate advantage. TSranca's 

 turbine of 1629, similar in principle and gen- 

 eral construction to the impact waterwheel, 

 had been reproduced successfully by Dr. La 

 Val and is in extensive use in a form illus- 

 trating modern scientific construction. In 

 1884, Mr. Parsons began his work on his now 

 familiar form of compound turbine, adopting 

 the type of wheel known in hydraulics as the 

 impact turbine. This proved practically suc- 



cessful, ultimately, and is now made in large 

 numbers for electric 'plants.' It has been 

 proved to be capable of as high economy as 

 the reciprocating engines of the best modern 

 constructors. 



In 1894, the same plan was adopted for en- 

 gines supplied to the Turhinia. The outcome 

 was the redesigning of the screw-propeller and 

 its method of application and the attainment 

 of a higher speed than had ever before been 

 recorded, 32| knots, 38 miles, an hour. The 

 steam consumption was 14J,- pounds per horse- 

 power-hour, a result better than was usually 

 obtained in similar craft with even triple- 

 expansion engines and under similar condi- 

 tions of steam supply. About 28 pounds of 

 steam were vaporized per square foot of heat- 

 ing surface of boilers. 



The Viper and the Oobra have been later 

 built on the same general plan and the former 

 became the record-breaking vessel for the 

 world, attaining above forty miles an hour 

 (37,118 knots, 43 miles) on the dimensions of 

 the regular 30-knot torpedo boat destroyer, a 

 length of 210 feet, a beam of 21 feet and with 

 350 tons displacement. Water-tube, safety- 

 boilers were fitted and the engines were of the 

 compound turbine tyije. 



A design for a war-vessel is hypothetically 

 proposed on this plan and Mr. Parsons con- 

 siders it possible to build a ship of 420 feet 

 length, 42 feet beam and 14 feet draught, hav- 

 ing 2,800 tons displacement, which should de- 

 velop eighty thousand horse-power and a speed 

 of 44 knots (over 51 miles) an hour. This 

 represents a concentration of power never be- 

 fore dreamed of by the engineer, far less at- 

 tempted or approximated, although an Ameri- 

 can designer, Mr. Mosher, has rivalled the 

 work of Parsons in smaller craft. 



Papers by Professor Ewing on the 'Struc- 

 ture of Metals' and by Sig. Marconi on wire- 

 less telegraphy fall into the same general cate- 

 gory of work in applied science, and those of 

 Lord Kelvin, Professor Dewar and others are 

 in the field of pure science and have special 

 interest through their promise of later utiliza- 

 tion. Sir Andrew ISToble presents a remark- 

 able and illuminating discussion of the mod- 

 ern explosives. E. H. Thueston- 



