Apeil 6, 1906.] 



SCIENCE. 



557 



tion to zoology was, however, an earlier paper 

 (published as his doctor's dissertation) on the 

 Spermatogenesis of Anasa tristis, which 

 formed one of the first car'efiil studies of the 

 history of the ' accessory chromosome ' since its 

 discovery by Henking, and which gave impor- 

 tant data for the general study of the repro- 

 duction problem in animals. He was a good 

 observer, an enthusiastic field naturalist, and 

 a master of the finer laboratory technique. He 

 bore with cheerful courage a malady that for 

 many years formed an obstacle to his scientific 

 activity and at length caused his death. He 

 had many interests outside the field of his 

 special work and was a generous and helpful 

 friend. 



E. B. W. 



MECHANICAL FLIGHT. 



Messrs. Orville Wright and Wilbur 

 Wright, of Dayton, Ohio, under date of March 

 12, 1906, have addressed the following state- 

 ment to the Aero Club of America : 



Thougli America, through the labors of Pro- 

 fessor Langley, Mr. Chanute, and others, had ac- 

 quired not less than ten years ago the recognized 

 leadership in that branch of aeronautics which 

 pertains to bird-like flight, it has not heretofore 

 been possible for American workers to present a 

 summary of each year's experiments to a society 

 of their own country devoted exclusively to the 

 promotion of aeronautical studies and sports. It 

 is with great pleasure, therefore, that we now find 

 ourselves able to make a report to such a society. 



'■' Previous to the year 1905 we had experi- 

 mented at Kitty Hawk, North Carolina, witli man- 

 carrying gliding machines in the years 1900, 1901, 

 1902 and 1903 ; and with a man-carrying motor 

 flyer, which, on the 17th day of December, 1903, 

 sustained itself in the air for 59 seconds, during 

 which time it advanced against a 20-mile wind a 

 distance of 852 feet. Flights to the number of 

 more than 100 had also been made at Dayton, 

 Ohio, in 1904, with a second motor flyer. Of 

 these flights, a complete circle made for the iirst 



Sept. 26 17,961 meters (lli/g miles) 



Sept. 29 19,570 meters (12 miles) 



Sept. 30 



Oct. 3 24,535 meters (15^4 miles) 



Oct. 4 33,456 meters (20% miles) 



. Oct. 5 38,956 meters (241/5 miles) 



time on the 20th of September, and two flights of 

 3 miles each made on the 9th of November and 

 the 1st of December, respectively, were the more 

 notable performances. 



" The object of the 1905 experiments was to de- 

 termine the cause and discover remedies for sev- 

 eral obscure and somewhat rare difficulties which 

 had been encountered in some of the 1904 flights, 

 and which it was necessary to overcome before it 

 would be safe to employ flyers for practical pur- 

 poses. The experiments were made in a swampy 

 meadow about 8 miles east of Dayton, Ohio, and 

 continued from June until the early days of Oc- 

 tober, when the impossibility of longer maintain- 

 ing privacy necessitated their discontinuance. 



" Owing to frequent experimental changes in 

 the machine and the resulting dififerences in its 

 management, the earlier flights were short; but, 

 towards the middle of September, means of cor- 

 recting the obscure troubles were found, and the 

 flyer was at last brought under satisfactory con- 

 trol. From this time forward almost every flight 

 established a new record. In the following 

 schedule the duration, distance and cause of 

 stopping are given for some of the later flights. 



" It will be seen that an average speed of a 

 little more than 38 miles an hour was maintained 

 in the last flight. All of the flights were made 

 over a circular course of about three fourths of 

 a mile to the lap, which reduced the speed some- 

 what. The machine increased its velocity on 

 the straight parts of the course and slowed down 

 on the curves. It is believed that in straight 

 flight the normal speed is more than 40 miles an 

 hour. In the earlier of the flights named above 

 less than 6 pounds of gasoline was carried. In 

 the later ones a tank was fitted large enough to 

 hold fuel for an hour, but by oversight it was not 

 completely flUed before the flight of October 5. 



" In the past three years a total of 160 flights 

 have been made with our motor-driven flyers, and 

 a total distance of almost exactly 160 miles cov- 

 ered, an average of a mile to each flight, but until 

 the machine had received its flnal improvements 

 the flights were mostly short, as is evidenced by 

 the fact that the flight of October 5th was longer 

 than the 105 flights of the year 1904 together. 



18 min. 9 sec. Exhaustion of fuel. 



19 min. 55 sec. Exhaustion of fuel. 

 17 min. 15 sec. Hot bearing. 



25 min. 5 sec. Hot bearing. 



33 min. 17 sec. Hot bearing. 



38 min. 3 sec. Exhaustion of fuel. 



