(769) 
Now this premifed, We are next^ with himj to fuppofe the 
Earth carried about with a double motion 5 The one Annual^ as 
( .fig. I. ) in B E C the great Orb, in which the Center of the 
Earth B^is fuppofed to move about the Sun A«. 
The other D/2^r«^/ 3 whereby the whole moves upon its own 
Axisy and each point in its furface defcribes a Circle, as 
D E F G. 
It is then raanifeft^that if we fuppofe, that the Earth moved 
but by any one of thefe motions, and that regularly, ( with an 
equal fwiftnefs^ ) the Water, having once attained aneqtiai 
l/w/^*^^ thereunto , would ftill hold equal pace with it; there 
bemg no occafion , from the Quickening or Slackening of the 
Earths motiooj (in that part where the Water lyeth) for the 
Water thereon either to be caft Forward or fall Backward^and 
thereby to aecumulate on the other parts of the Water : But 
the true motion of saeh part of the Earths furface being com- 
pounded of thofe two motions , thQ Annml and Diurmh ("the 
Annual in B E C being, as Gaiilceo there fuppofethj^ about three 
times as foft as a diurnal motion in a great Circle, as D EF^ ) 
while a Point in the Earths furface moves about its Center 
from G. to D. and E. and at thefame time, its Center B. be car- 
ried forwards to C; the true motion of that Point forwards, is 
made up of both thofe motions ; to wit^of B to G, and of G to 
E; but while G moves by D to E, E moves backward by E 
£0 G5 contrary to the motion of B to C ; fo that the true moti- 
on of E^ is but the difference of B C, and EG: Cfor, befide 
the motion of B, the Center G is alfo put forward as much as 
from G to E; and Eput backward as much as fromE to G: } . 
fb thattheZ)farwa/motion,in that part of theEarth, which is next 
the Sun, as E F G, doth abate the progreis of the Annml^(and ' 
moft of all at F ;) and in the other part, which is from the Smij 
as G D E5it doth increafe it, (and moft of all at D.) that is,in the 
day time there is abated,in the night time is added to the Annual 
motion, about as much as is G E, the Earths Diameter. Which; 
wo^ld afford us a Caufe of two Tides in twenty four hours ; the 
One upon the greateft Acceleration of motion, the Other up- 
on its greateft Reiardation, 
And thus far Galilao s Dilcomft holds well enough^ But then 
