184 ANNUAL OF SCIENTIFIC DISCOVERY. 



attended to in our Universities than it deserved. He could not also admit 

 that so little had been done by the methods heretofore in use: and although 

 he considered a vigorous integration of the equation to be very important, yet 

 he considered much had been done even by himself by using the method of 

 successive approximations, similar to that adopted in the Lunar and Plane- 

 tary Theories. Of this he adduced several examples, such as those in his 

 article on Waves and Tides in the Encyclopaedia Metropolitana, and the non- 

 reflection of breaking waves, while at the same time, like the whisper in the 

 gallery of St. Paul's, they were conducted along a smooth Avail up to which 

 they moved very obliquely ; also bores and quiet tide-waves, and some others. 

 He also could not subscribe to the objection that assuming the differential 

 coefficient to be unity required that the air should be so constituted that 

 pressure in a given direction should be accompanied by a motion of the par- 

 ticle in the opposite direction, for this frequently happened where the particle 

 was already in motion. Mr. Earnshaw explained that what he meant to con- 

 vey was, that the pressure should be the originator or cause of motion in the 

 opposite direction. 



NATURAL DIAPASON. 



M. Cagniard de la Tour, a French physicist, has satisfied himself that he 

 hears the sound la of the musical scale sounding within his head when he 

 agitates it from side to side; and Mr. Jobard has confirmed this observation 

 in himself, and asserts that any one can verify it, if he will disembarrass his 

 neck of the cravat and collar, and place himself apart from all noise. 



Mr. Jobard thus explains the fact : This natural la is caused by the contact 

 of the malleus against the incus in the ear a contact easily made by a rapid 

 movement of the head. Mr. Jobard goes still farther : for according to him, 

 those persons who, on shaking the head, hear two la in perfect unison are 

 born musicians ; they have the voice and ear perfectly correct. But those 

 that hear la only in one ear, have an imperfect appreciation of sounds; and 

 those who perceive two different sounds, the la and another note, not only do 

 not love music, but detest and avoid it; and he proposes by this method to 

 discover among young people those who may become musicians. 



Mr. Jobard has still under inquiry, whether the note which is produced in 

 the head by a quick motion is the same or not in all persons. The question 

 will be of difficult solution; for the la of the opera of Paris is different from 

 that of the theatre of Strasbourg, Lille, Vienna and London, and that this la 

 is becoming more and more elevated, so that in twenty years it will corre- 

 spond to many more vibrations than now, and be therefore still more acute. 



ON THE SONOROUS ACTION OF JETS OF BURNING GAS. 



At a recent meeting of the Boston Society of Natural History, Prof. Rogers 

 called attention to the curious phenomena connected with the sonorous 

 action of jets of burning gas, which have lately been observed by Prof. Tyn- 

 dall and others. 



The production of a musical sound by a small flame of hydrogen gas, 

 burning within a tube, has long been one of the most familiar of lecture- 

 room experiments. Prof. Faraday, in one of his earliest investigations, 

 showed that this musical effect was not confined to hydrogen, but could be 

 produced with flames of carbonic oxide, common illuminating gas, and 



