422 



SCIENCE. 



[Vol. II., No. 34. 



brake is automatic, the fracture of wire or 

 draw-gear ringing bells on engine and caboose, 

 and warning both engineer and conductor that 

 the train has parted, each being then at libert}' 

 to apply the brake or not, on his portion of the 

 train, as he maj'' deem best. Owing to the 

 s^'stem of circuiting, the brake maj- be out of 

 order on one car without affecting the rest of 

 the train. 



The street-car starter and brake exhibited 

 by Charles T. Brown & Co., Chicago, is an 

 ingenious device for storing the momentum 

 which is destroyed by the usual form of brake, 

 and utilizing it for restarting the car. The 

 motion is not checked bj' friction, but b}' the 

 axle, which, through suitable gearing, winds 

 up a spiral spring, the power of which is avail- 

 able to again put the car in motion. The 

 mechanical details appear well worked out, and 

 the car can be run in either direction, and 

 stopped or started on either up or down grades. 

 The heavj' pull necessary to start a car is 

 very severe on horses, and this invention 

 would appear to be useful in saving much 

 wear and tear of horse-flesh. 



D. H. O'Neale Neale. 



A HEARING OF BIRDS' EARS.^—l. 



The ' musical class ' of vertebrates enjoj' tlie 

 sense of audition to a high degree. Otherwise 

 birds would cease to sing. Thej' are the onlj' 

 animals besides man whose emotions are habit- 

 uall}' aroused, stimulated, and to some extent 

 controlled, hy the appreciation of harmonic 

 vibrations of the atmosphere. Most birds ex- 

 press their sexual passions in song, sometimes 

 of the most ravishing quality to human ears, as 

 that of the nightingale, skylark, or blue-bird ; 

 and it cannot be supposed that thej^' do not 

 themselves experience the effect of music in an 

 eminent degree of pleasurable mental perturba- 

 tions. The capabilit}' of musical oppression 

 resides chieflj^ in the male sex ; the receptive 

 capacity of musical affections appears to be 

 better developed in the female. There is, how- 

 ever, no anatomical difference in their ears. 

 Quickness of ear is extraordinarj- in some birds, 

 as those of the genus Mimus (mocking-birds) , 

 which correetlj' render anj' notes they maj' 

 chance to hear, with greater readiness and ac- 

 curacy than is usually within human compass ; 



I Complementary to the ai-ticle entitled ' Tbe nature of the 

 human iea\^ovQ.\'\ion&,^ JournaL of otology, January, 1832. Some 

 portions of that article may perhaps be made clearer by the pres- 

 ent one, especially those relating to the parts of a temporal bone 

 as elements of mandibular and hyoldean arches. Figs. 1-4 are 

 borrowed from Prof. W. K. Parker's admirable essay on the de- 

 velopment of the fowl's skull, in Encycl. Brit., 9th ed.,art. Birds; 

 figs. 5-9 are from Prof. 1. Ibsen's beautiful memoir, as cited in 

 the text. 



•and it may be reasonably doubted whether an\- 

 other animals tlian some of the world's greatest 

 musical composers have a higher e-xperience of 

 acoustic possibilities than manj' birds possess. 



Birds' ears have nevertheless a simple ana- 

 tomical construction, in comparison with those 

 of mammals. The auditory organ is decidedlv 

 of the reptilian type ; and the arrangement of 

 the parts is, on the whole, quite like that of 

 reptiles. Thus, the cochlea, which in mam- 

 mals makes from one and a half to five whorls 

 (two and a half in man) , is simplj- a strap-like 

 prolongation from the vestibule, lacking modio- 

 lus, lamina spiralis, etc.; the stapes is the • 

 onlj- perfected ossiculum auditus ; the incus is 

 scarcely recognizable as such, and inseparable 

 from tlie stapes ; the malleus is immense, but 

 outside the ear, furnishing the articulation of 

 the lower jaw, of the zygomatic arch, and of the 

 pteiygo-palatal bar ; the tj'mpanic bone is rep- 

 resented at most by a few specks of ossifica- 

 tion. There is ordinarily no external ear ; the 

 whole tympanic cavitj' is exposed on removal 

 of the membrane, which lies very superficial ; 

 the eustachian tubes unite before opening into 

 the pharynx ; the periotic bone, constituting the 

 otocrane or skull of the ear, is less compact 

 and precise than the ' petrous portion ' of the 

 mammalian temporal bone, its three bon}' ele- 

 ments being more distinct ; no mastoid por- 

 tion is recognizable as such, but pneumatic 

 cells of diploe are numberless, and there is 

 direct passage of air from the ear into the hol- 

 low of the lower jaw ; one of the semicircular 

 canals invades the occipital bone. Other pe- 

 culiarities will appear as we proceed with our 

 description, in which comparisons will be chiefly 

 made with the human ear. 



Most birds have no external ear, in the 

 sense of a fleshj' conch or auricle. In bald- 

 headed birds, the meatus externus appears as 

 a roundish orifice at the lower back corner of 

 the head, just above and behind the articulation 

 of the lower jaw. In neaiij' all birds, the 

 opening is hidden by an overlying packet of 

 feathers, coUectivelj' termed the auriculars or 

 ear-coverts, on simplj"^ raising and reflecting 

 which the meatus is exposed. The auriculars 

 are peculiarlj' modified feathers, having loos- 

 ened barbs, doubtless to lessen interference 

 with the passage of sound. In a few birds the 

 border of the meatus develops a slight tegu- 

 mentary fold, partially occluding the orifice. 

 In various owls, as of the genera Strix, Aluco, 

 Asio, Nj'ctala, but not even throughout this 

 group of birds, an immense tegumentarj' oper- 

 culum, or ear-cover, is developed, which flap 

 shuts down upon the ear-opening like the lid 



