EECEEATIYE SCIENCE. 



265 



The great naturalist worked ou till he 

 died. • After exhausting, as we may say, the 

 birds of America, he, in 1839, turned his at- 

 tention to the animals ; with what result we 

 have shown. He traversed almost every foot 

 of ground in the North American continent. 

 He wrought in his age with the ardour of 

 youth. The publication of the second vo- 

 lume of this valuable addition to natural 

 history, was issued at IS'ew York in 1850, 

 less than a month before his death. 



His work was done, his long wanderings 

 had ceased, and the time had come when he 

 should be called to his final home. He him- 

 self was aware of this. In the almost last 

 letter which he wrote are these words : — 

 " Once more surrounded by all the members 

 of my dear family, enjoying the countenance 

 of numerous friends who have never deserted 

 me, and possessing a competent share of all 

 that can render life agreeable, I look up with 

 gratitude to the Supreme Being, and feel that 

 I am happy." 



This was written at the end of 1850 — on 

 the 27th of January, 1851, Audubon had 

 ceased to live. Hain Feiswell. 



DETEEMINATIOJN" OP LATITUDE. 



It is well known that our earth has a motion 

 from west to east, caused both by its diurnal 

 rotation and annual revolution. It is evident 

 that were the earth a homogeneous sphere, 

 and at rest, the pendulum would describe 

 that line which, if continued, would pass 

 through its centre ; in other words, it would 

 faU vertically. But as the earth is neither 

 homogeneous in figure or structure, nor at 

 rest, it is reasonable to suppose that the pen- 

 dulum does not fall vertically. Its want of 

 uniformity in structure and figure must in- 

 fluence this, while its motion must incline 

 the pendulum in the said direction. It is 

 well known that all bodies have an impulse 

 m the direction of any motion to which they 

 are subjected, whence it follows that the 



pendulum must not only have this tendency, 

 but have its position altered in consequence. 

 Other bodies may have this influence with- 

 out their position being afiected by it. The 

 luggage in a train, for example, has a ten- 

 dency to move in the direction of the motion, 

 and would be shot forward with no small 

 force were it suddenly to cease. Priction, 

 or direct prevention, which may perhaps be 

 termed statical pressure, may prevent motion ; 

 neither of which, however, materially affect 

 the motion of the pendulum ; the friction of 

 the cord and the barrier of the atmosphere, 

 supposing the pendulum not hanging in vacuo, 

 are not obstacles affecting the present con- 

 sideration. It is remarked by Hunt (" Ele- 

 mentary Physics "), that a falling body has a 

 tendency towards the east, which fact is 

 known to all philosophers ; and, although I 

 have never met with the statement, seems 

 impossible not to apply to the pendulum. If 

 this is the case, it is evident that the leaning 

 will increase with the motion, and conse- 

 quently reach the maximum at the equator. If, 

 therefore, a pendulum were caused to register 

 its position, magnified by accurate and suscep- 

 tible leverage, it could always be known in 

 what latitude the observer stood, as soon as 

 a scale had been properly graduated, and 

 marked according to observations. The in- 

 strument would not be complicated, although 

 great niceness, especially as regards the 

 contraction and expansion of its parts, 

 would be necessary to render it completely 

 effectual. The pendulum, the leverage con- 

 nected with it, and the scale, are of course 

 its only essential parts. The leverage, if 

 not always necessary, is of course so when 

 the alteration of terrestrial position would 

 be small, in order that the change in the 

 position of the pendulum should by suffi- 

 cient enlargement be distinctly perceived. 

 It need not be said that an index, or pointer, 

 should be connected with the leverage, and 

 pass over the scale. 



J. A. Davies. 



