-106 Observations on the Phcenomena 



and momenta, arcfixed quantities, the density only being variable: 

 whence it is evident that the sohdity of the spheres only is as 

 the cubes of their radii. The solidity of each spherical stratum 

 bears no analogy to this proportion; and so far from the increas- 

 ing bulk in enck stratiun being inversely as the cube of the radii, 

 it is absolutely in a direct arithmetical proportion. In ascer- 

 taining the soliditv of a spherical shell, it is requisite that the 

 solidity of all the interior spherical shells be deducted from the 

 solidity of a sphere whose diameter is equal to that of the su- 

 perior shell, in order to obtain the solidity required. 



10. Sir Richard, page 91, objects to the words attraction and 

 repuhioTi: as to attract and to repel are active verbs implying 

 an a^ent and a patient, it would be evidently absurd, he remarks, 

 to say of two ships sailing towards each other at sea, that they 

 .atjtract one another. The impropriety in the sentence I ac- 

 knowledge, but the absurdity originates in his reference of that 

 eifect to attraction which in reality is produced by the wind. 

 The absurdity therefore evidently attaches itself with the im- 

 propriety of his allusion, or in misapplying the word. In re- 

 spect to agents, I answer that the effects of an agent cannot be 

 ■visible unless another body exist, on which it operates. In short, 

 such quibbles are beneath notice. 



1 1. Tlie rotation of a point on the earth's equator in one se- 

 cond of time is stated at 1250 feet, vide page 17: but this state- 

 ment is erroneous, as it ought to be 1523 feet; the earth's dia- 

 meter being 7912 miles. 



12. The orbicular and rotatory motions of the planets are in a 

 direction from west to east ; the orbicular motion of Saturn in 

 one second is 31997 feet: its rotatory motion round its axis 

 in one second, is 349S7 feet in the same direction ; conser 

 qvientlv its combined motions are 66984 feet per second. It is 

 therefore preposterous to assert that a detached body can rest 

 on his surface in this situation without being hurled off in the 

 direction of a tangent, to the radii of its orbit. On the con- 

 trary side of the planet its rotatory motion is in the opposite 

 direction, and its secondary velocity equal to 2990 feet, its mo- 

 tion in this case being retrograde. Hence all loose or detached 

 bodies would be hurled from its surface, the gaseous medium 

 beini^ insufficient 'o constrain it to revolve in a circle. 



13. Sir Isaac Newton investigated the properties of iwtices, 

 in order to ascertain whether the celestial motions could be ac- 

 counted for thereby; and he has proved that the celestial bodies 

 are not carried round in vortices, which he has siiown to be ab- 

 surd and impossible: as comets move in orbits in all directions, 

 these vortices must be composed of such fluid matter as has 

 neither friction nor resistance, and that one vortex must be pe- 

 netrable 



