VOL. XXXVI.] PHILOSOPHICAL TRANSACTIONS. 381 



but -f of the weight, must be -f part of it: and if the angle of the plane's 

 inclination was but 1 1° 32', the power would be 4- of the weight, &;c. 



Corol. 1. — Hence it follows also, that if the plane be be horizontal, no force 

 of the power will be lost, because eg : cf :: cg ; cf. 



Scholium. — As the friction of the .winding of the ropes, such as bc in the 

 new way, is greater than the friction of the pivot in the old way, besides 

 the friction of the collars of the counterpoise to the engine, so that friction 

 diminishes, as the ropes bear less weight, according to the diminution of the 

 angle of the plane; and when the plane is horizontal, and without a counter- 

 poise, even then the winding up of the ropes, and pressure of the roller against 

 the plane, is equal to the friction in the common way. 



Of the EquultHs or JVooden Horse of the Ancients. By Mr. John Ward* 

 Prof. Rhetoric in Gresham College, and F. R. S. N° 412, p. 213. Abridged 

 from the Latin. 



For what purpose the equuleus or wooden horse was first instituted, and to 

 what use it was applied, is pretty evident from several passages in ancient 

 authors. But since none of them have described its figure, and the manner of 

 constructing it, learned men have run into various opinions, and those widely 

 differing from each other. And indeed this will not seem surprizing to any one 

 who considers, how difficult very often it is to determine with certainty on 

 things that have been in disuse for several ages, and removed from our view; 

 especially, if the ancient authors, who mention them, do it only slightly, and 

 do not fully describe them. This, then, was the case with the equuleus; nor 

 did any of the learned who, after the revival of literature, undertook to de- 

 scribe this machine, seem to Mr. Ward to have done it with such success, as that 

 their description agreed in every respect with what the ancients deliver about 

 it. So that he had entirely laid aside all hopes of obtaining any greater cer- 

 tainty in this affair: but being favoured with the sight of some papers sent to 

 Dr. Mead from Rome, in which were delineated several figures of an ancient 

 work, still extant there; among others he happened to light upon one, drawn 

 from a marble, in the prince of Borghesi's palace, which, as he conjectured, 



* Dr. John Ward was a very useful member of the Royal Society, and for many years one of 

 the Vice Presidents. He was born at London in 16'79; and in 1720 was chosen professor of Rhe- 

 toric in Gresham College, where he died in 1758; being also one of the trustees of the British 

 Museum. He wrote Lectures on Oratory, in 2 vols ; also the Lives of the Professors of Gresham 

 College; with a great number of learned papers in the Philos. Trans, chiefly on curious subjects of 

 antiquity, contained in most of the volumes from vol. 36 to vol. 4-9. His writings are replete 

 with learning, and curious remarks; but his manner is rather laboured and tedious. 



