‘144 Remarks on Dr. Enfield’s Institutes 
properly referred to the subject of apparent velocity, than 
es parent magnitude. As referred to the head of appa- 
‘Tent velocity, the proposition might have been thrown into 
following simple and not inelegant form: “ When a body 
moves uniformly in a- right line, its apparent velocity will 
be “agra as the square of the distance from the eye.” 
In demonstrating the 83d and 85th propositions, it is 
stated as erie reason why the image produced by a convex 
or concave lens is erect, that the axis of the peneils which 
re from the extremities of the object ‘only cross one 
“another at the lens.” It should be, “beeause they only 
‘ross one another at the eye.” kon cles — pass 
ot 
& meet te added, that’ es all 
ree in’ this genie which state the effect of 
: aban sa gras maguitude, have rosea demon- 
_eedes from the lens, “te rays oie enter the: papi at froma 
bd same point of the object, gradually change: the axis of 
“the cil, instead of coine coinciding | with the centre oft the lens, 
© 
the Ve. 
ject is above or be rth “Hence it is enpepere o assume 
that ihe Even from A (figs. 8 and 9) diverges as if from the 
same point D for all distances of the eye from the lens. 
The assumption is erroneous, except when the object is 
extremely re. and it ought: not to be made even in ne 
ease rn 85 oof.* 
“a Of this proposition Were one of the least ae 
‘se it eel be desirable that it should have a more satis- 
factory demonstration than its poneent one, which on several 
. accounts i is wholly inconclusive. 
e semarks made in this paresrenh. x are ee ennal app licable tot amp 
in the e sucee eding ¢hapter, whie 23 relate M vision as affecte hy 
