VOL. Vlir.] PHILOSOPHICAL TRANSACTIONS. 79 



An easy Way of raising Fruit-trees to any Number desired. By Mr. Lewis of 

 Tottenham High-cross. N* 95, p. 6067. 



Take a piece of the root of any apple or pear-tree, &c. about 6 inches long, 

 and tongue-graft, a graft of an apple or pear into the root. The way of tongue- 

 grafting is, to cut the root sloping about 1 inch, and the graft sloping in like 

 manner 1 inch; cutting both very smooth. Then cleave the root and the graft 

 likewise about 1 inch, and enter them into one another, that the sap of the 

 graft may join to the sap of the root as much as you can. Lap the jointed place 

 about with a little hemp or flax-hurds ; set the root so grafted into the ground 

 about 10 or 12 inches deep, so as the joint may be covered at least 4 inches 

 under the earth, that it may not be bared at any time, but kept moist by the 

 earth. 



An Account of some Books, N° 95, p. 6068. 



I. Christian! Hugenii Zulichemii Horologium Oscillatorium. Par. 1673, in 

 folio. 



This eminent mathematician divides this treatise into five parts; of which, 

 the first contains his description of the pendulum watch. — The 2d treats of the 

 descent of heavy bodies, and their motion in a cycloid, that is, in a line which 

 a nail, fastened in the circumference of a running wheel, by its continued cir- 

 cum rotation designs in the air. — The 3d of the evolution and dimension of 

 curve lines. — The 4th of the centre of vibration. — ^The 5th of the construction 

 of another watch, in which the pendulum moves circularly ; with some theorems 

 of centrifical force. 



A simple pendulum being no certain and equal measure of time, since the 

 larger excursions are observed to be slower than the smaller, the other has, by 

 the aid of geometry, discovered a way of suspending the pendulum, by finding 

 out a certain curve line fit to give it the desired equality, which having applied 

 to watches, their motion has by this means been rendered so constant and cer- 

 tain, that by frequent experiments they are now known to be exceedingly use- 

 ful, both in astronomy and navigation. This being the cycloid abovementioned, 

 our author gives a very accurate demonstration of it, with some new demon- 

 strations on the natural descent of heavy bodies. 



But then that this cycloid might be adapted to the use of pendulums, he 

 thought himself obliged to enter upon a new consideration of curve lines, viz. 

 of those, which by their evolution generate other curves. Whence resulted the 

 comparison of the length of curve lines with straight ones. — Besides, for the 

 clearer explication of the nature of the compounded pendulum, he subjoins a 



