226 PHILOSOPHICAL TRANSACTIONS* [[aNNO 1705. 



the vestibulum, through which the portio mollis enters by 5 holes, where its 

 twigs or branchings are presently expanded into a very fine membrane, which 

 lines all its surface, being further continued through all the semicircular ducts : 

 this nervous expansion, from its resemblance to a very thin and narrow ribbon 

 or fillet, he calls zona, and from its use, sonora, of which he reckons 3, accord- 

 ing to the number of canals: he says, these zonae sonorae are very conspicuous 

 in several quadrupeds, and in volatiles especially. 



The labyrinth has both veins and arteries, though its cavity is not invested 

 with any periosteum to sup[)ort them ; but whether they proceed from those 

 diffused through the os petrosum, or that they enter together with the auditory 

 nerves, he cannot positively determine. He doubts not but these vessels are 

 also accompanied with lymphatics, as well as those of the retina, as he has 

 observed in the eye of an ox. For the use of the parts, on which our authour 

 is exceedingly large, I refer the reader to the book itself, which is enriched with 

 a number of curious plates, especially of the parts relating to the ear, drawn 

 from the life, and well engraven. 



Concerning an Improvement of the Hessian Bellows, &c. By Mr, D. Papin. 



N°300, p. 1990. 



I am busy at present for a coal-mine, which has been left off, because of the 

 impurity of the air : I have therefore improved the Hessian bellows, an account 

 of which was printed at Leipsic, in Actis Eruditorum, anno 1699, with this 

 title, Rotatilis Suctor et Pressor Hassiacus; which may be applied for wind as 

 well as for water. The shape of the tympanum was cylindrical, as represented 

 fig. 16, pi. 8 ; where dafc is the circumference; cp, dp, ap, are the radii, 

 which bear the wings cm, Dn, ao ; Be is the aperture through which the wind 

 must be driven, in the direction of the tangent cb : and it may be observed that 

 when the engine is working, every wing's from the end of the aperture e, till it 

 comes to the beginning of the same aperture c, drive always the same air, with 

 the same swiftness, and at the same distance from the centre : so that in going 

 over all that circumference, the air finds resistance by friction, and gains no- 

 thing at all. I therefore now make the circumference of the tympanum in a 

 spiral shape, as fig. 17, where the spiral circumference is apgb; the radii are 

 ap, cp, dp, &c. the wings are am, cn, do, &c. and the aperture is ab. And it 

 is to be observed, that every wing, in going round, drives new air : because the 

 air which is first in motion finds room to recede from the centre, towards the 

 spiral circumference, and so gives room for new air to come to the wing : and 

 when the wings come near to the aperture, they drive their new air into the 



