16 Rev. J. Challis's Remarks on Lagrange's 



dred and twenty feet*, sometimes to the height of one hundred 

 and fifty feet, and even, as it is said, to the very extraordinary 

 height of upwards of two hundred feet, being about seven feet 

 in circumference at the base, but gradually tapering towards 

 the summit, and thus forming with its lofty crown of fronds 

 the noblest object of vegetable creation. 



Where casts the mountain palm, on high, 



Its lengthen'd shadow from the evening sky. — Montgomery's West Indies. 



The trunks of oak-trees attain, oftentimes, to a very great 

 size. We may take the testimony of Ovid with regard to the 

 oaks of ancient Italy ; 



Saepe etiam, manibus nexis ex ordine, trunci 

 Circniere modum; mensuraque roboris ulnas 

 Quinqne ter implebat. — Metamorph. viii. 747- 



and we have only to make use of our own optics with regard 

 to the existing oaks of old England. At Cowthorpe near 

 Wetherby, in Yorkshire, there is now growing an oak that 

 measures seventy-eight feet in circumference close to the 

 ground, and forty-eight at the height of a yard. It is said to 

 have begun to decline in the reign of Queen Elizabeth, and 

 though now much in decay, is still likely to stand for many 

 years. But the trunk of Adansonia digitata is beyond all 

 comparison the largest that is yet known. Adanson in his 

 voyage to Senegal, saw a tree of this species having a trunk 

 that measured twelve feet in height, by twenty-seven feet in 

 diameterf. Such trunks are sometimes hollowed out, and con- 

 verted into a sort of house or cabin, serving for the abode of 

 several families of negroes. Nor is this all ! From the leaves 

 they obtain a pleasant seasoning for their food ; from the root 

 a purgative; from the bark a pectoral anodyne; from the 

 parenchyma of the trunk, a cataplasm that cures cutaneous 

 eruptions ; from the fruit they compose an agreeably astrin- 

 gent draught; they eat the kernel; they smoke the calyx; 

 and they use the capsule as a spoon J. 

 [To be continued.] 



V. Remarks on Lagrange's Proof of the Principle of Virtual 

 Velocities. By the Rev. J. Challis, Fellow of the Cam- 

 bridge Philosophical Society. % 

 THERE is one part of the celebrated Proof of the Prin- 

 ciple of Virtual Velocities at the beginning of the Meca- 

 nique Analytiqne, which has been thought to be obscure, or 



* Sloanes's Natural History of Jamaica, 

 f Fam. des Plantes, Prcf. ccxii. 

 \ Naufrage de la Fregate la Medusa, 1816. 

 § Communicated by the Author. 



