June 24, 1904.] 



SCIENCE. 



955 



prime motor sufficiently reliable was the steam.- 

 engine. 



To get the strongest and the lightest was 

 the problem. 



It is true that carbonic acid had been lique- 

 fied some years before then, but no one knew 

 how to harness it. 



Having determined the probable force want- 

 ed, engine builders were found who agreed to 

 make the engine light enough and of sufficient 

 horse power, and the frame of the machine 

 was set up at Hoboken, IST. J. The fans were 

 made for the lifting and driving, and the in- 

 termediate gear of bronze was cut. The body 

 of the machine was complete. 



At this stage it seemed that it only re- 

 mained to get pressure enough upon the pis- 

 ton of the engine and maintain that pressure. 



During the siege of Fort Wagner before 

 Charleston we had used calcium lights, and 

 had had great trouble to make the gas holders 

 tight enough to prevent leak at high pressures. 

 Mr. Mirriam, of Springfield, Mass., had suc- 

 ceeded in the field by a new method of floating 

 the joints. Bennett and Eisley, of Greenwich 

 Street, New York, who undertook the engine, 

 believed that they could make the joints of 

 the boiler, the gaskets, the grummits and 

 moving parts of the engine so as to work well 

 under the required very high pressure of 

 steam, by their new process, which seemed 

 reasonable. Weeks, however, ran into months. 

 They were unfortunate in their experiments, 

 and the needed force of steam was not reached 

 before the coming of Appomattox. 



A description of the machine with a gen- 

 eral and some detail drawings with tabulated 

 data of the lifting capacity of the fans was 

 filed with a rough model in the engineer de- 

 partment of the army at Washington, D. C, 

 and a copy of the general plan was given to 

 Mr. Prentice, whose office is now at 44 Broad- 

 way, New York City, and the Duke of Argyle 

 was informed of what had in a general way 

 been done by the army. 



My conclusion was that at that time no 

 existing machine would develop power enough 

 to fly mechanically, without the use of gas- 

 holders. 



The use of liquid carbonic acid gas, COj, 



has changed the situation. Valves have been 

 made to work well at great speed under three 

 or four times the highest pressure of steam 

 applied to reciprocating engines, and about 

 five years ago a report was so made to the 

 chief of engineers of the army. 



The elimination of the boiler, water and 

 fuel and the substitution of stored energy in 

 the shape of liquid 00^ greatly reduces the 

 weight of machinery, and the conclusion 

 reached at the last analysis of this problem is 

 that for army use a radius of action of about 

 eight hundred miles is now attainable, after 

 some experimentation, as the chief difficulty, 

 the valves, have already been tested to a suc- 

 cess with pressures as high as are necessary. 



Nothing is known by the writer of the de- 

 tails of the machinery recently tried by the 

 brothers Wright in North Carolina, except 

 that obtained from imperfect newspaper ac- 

 counts, but from what has been published it 

 would seem that their machine is very much 

 like, if not identical, with the army machine 

 here described; but whether this is so or not, 

 they are to be most heartily congratulated 

 upon the measure of success that has crowned 

 their efforts, and this kind thoiight extends to 

 my friend of years gone by — Chanute — who is 

 reported to have helped them. 



Edward Wellman Seeeell. 



West New Brighton, 

 Staten Island, N. Y. 



notes on animal behavior. 

 To THE Editor of Science : It has been 

 suggested to me that it would be worth while to 

 put on record two or three rather curious 

 instances of animal behavior which have come 

 to my notice during the past few weeks. The 

 subject of these observations is a two-year- 

 old black-and-tan terrier belonging to my sis- 

 ter. A few weeks ago as the family was at 

 dinner one evening my mother said, 'What 

 did the postman bring this afternoon ? ' ' Only 

 a couple of advertising cards,' said my sister, 

 ' which I threw in the waste-basket.' Nothing 

 more was said on the subject, but a moment 

 later the dog, who had been sitting on a chair 

 in the same room, ran to the basket and, taking 

 one of the very cards referred to in his mouth. 



