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amended, that I could sec thc Greenneß of the Garden, and Pasture s in astand Verdure, whereas he köre the usc of them, all dark Colours had thefame Hue to my Eye.

f. yis- I have sometimes put Convex-Glassts (Tor a Tryal) into my Tubes- but Ifound the Prints, tho’something larger, yet not so clear, sodistinct/ norsopleasing to the Eyc,as when I used the empty Tapers. I find my seif best at easewith those Leathern Tubes that are made without any fastening to the Boneof the Spectacles; for as they hang in that slight mannet, I can with atouch of my Finger raise them up or bow them down, divide or unite themto take in the fame Object. *

». 4°. p. toi. I 5 ,und at sirst a great Difcouragement in the difficulty of using them, sothat I could not endure the Trouble above 2 Hours at a time; But by*thePractice of a Week or a Fortnight, I found them an Eafe and Pleafure to mefor 12 at least of each 24 Hours. And by all the Tryals which I have yetmade upon others, whether Pore-blmd , or of faint Sight decay’d by Ageor however weaken’d, it proves a very great Aid. For the Pore-blind theymust be made /horter: For the decay'd by Age, they may be langer.

c™<rm»sD"f- XVII. A Young Gentleman, who was born Dias , and continuednist -, by Dr. w. Dumb till his Age of 10 or n Years, was committed to my Gare. HisHolder. «-Z5- t- Rother when fhe was great with him, reeeived a fudden Fright j by Qcca-sion whereoh, the Child’s Head and Face were a little distorted, the wholerig'nt side ( as I remember) being fomewhat elevated, and the lest de-press’d; so that the Passage of his lest ear was quite fhut up, and thatof the right Ear proportionally distended, and too open. I found, uponExamination, that the Auditery Nerve of this right Ear was not perifht:And I sopposcd the Defcct to lyein the want ofdue Tension of the Tympa-num of his Eir; whosc use I took to be only to preferve the AuditoryNerve, and Brain, and inward parts of the Ear, from outward Injury byGold, Dust, &c. For it is requisite that the Tympanum be Ten/e andhard sirctched j othtrviise thc Laxneß of that Membrane will certainlyDead and Damp the Sound. The Tension of this part is the PrincipalOffice of the 3 Officies, vix „ the Malleus, Incus, and Stapes ; whereof theStapes is fixt to the inner Bone, and part of the Malleus to the Tympanum,and the /«««between them joyn’d on one partto the Malleus, and on theother to the Stapes by Ginglymoide Joynts, and by the help of a Muscledrawing the Incus, these 5 Bones are brought to a Curv’d or ArchedPosturc, and the Stapes being fixt unmoveable the Malleus yields, to bringthe Terms of that Eine nearer, in proportion as it is curved, and drawsthe Center of the Tympanum, stretchingthe furface of it from a Plain to aConoide Figure, witnin the fame Circumference. And 1 conctive the Acti-on of this Muscle does ordinarily and constantly draw \VzTympamm to amoderate Tension ; but when we have Occafion to listen, and give a moreparticular Attention to some found, the Action of that Muscle is then moreIntense, and the Tympanum is drawn to a more than ordinary Tension, soto facilitate the Passage of the Sound.

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