f 3 6 ° ] 
point T in the line OM, produced, inftead of com- 
ing from S. And a tube capable of receiving the 
ball, would allow the ball to pafs through it without 
finking its fides, if it were inclined forward in the 
direction O M ; which it would not do in any other 
htuation. The angle OMN or SMT anfwers to 
the aberration ; and fuppofing S to be the fun, and 
E, the earth, this angle is 20"; and the general 
effedt is, to make the fun, or any fixed ftar, to appear 
farther that way towards which the earth is mov- 
ing. 
2. Let us fuppofe another veffel V, between S 
and E, failing the fame way as E, in a parallel 
dire&ion. If both the veffels failed with the fame 
velocity, a ball from V coming to M, would go 
right acrofs to N, juft as if both of them had been 
at reft ; becaufe the ball, while crofting the veftel E, 
would be carried juft as far to the right hand as the 
points M and N are. And a tube to receive it rauft 
be held in the direction MN. So here would be no 
aberration of the veftel V. 
3. Suppofe V to move the fame way, but flower. 
A ball from V would now be really carried forward, 
that is, to the right hand, though not fo far as in the 
fecond fuppofition ; and therefore would be left be- 
hind in refpedt of the veftel E 3 and fo, would 
come to the fide of the veftel fomewhere between O 
and N ; but the greater its velocity towards the 
right, the nearer to N. So that if the velocity of 
V were to be continually increafing from nothing 
till it became equal to that of E, a tube to receive 
the ball mull; be held firft in the direction O M, look- 
ing forward, and afterwards, more and more in- 
1 dined 
