An Extract of a Letter from Sir Conrad Sprengell, M. D. R. S. S. & Coll. Med. Lond. Licen. to Dr. Mortimer; Wherein He Inclosed the Foregoing Account of the Plica Polonica; Together with an Article from the Brellam Sammlung von datur und Medicin, &c. Gelchichten upon the Same Subject, Translated from the High-Dutch by Dr. Mortimer, R. S. Secr.

obiit. Foeminam istam adhuc viventem vidit non tantum, & hac figura ad vivum depingere curavit, sed ipsam Plicam post obitum resectam secum Wittebergam attulit Clariss. D. Flouricke dicti Principis Medicus. Erat autem Plica quatuor ulnas longa, palmum lata, duosque pollices crassa, sed altero tanto longior foret, ipso referente, nisi magna ejus pars, tetaporis quo æegra decubuit diuturnitate, fqualore & attritu consumpta fuisset. Hunc ergo Casum penitus extraordinarium, illustrissimæ Societati Regali exponere volui. Spero autem fore, ut imposterum de circumstantiis singularibus hujus casus a laudato Viro certior reddar, quas alio tempore communicabo. VIII. An Extract of a Letter from Sir Conrad Sprengell, M.D.R.S.S. & Coll. Med. Lond. Licen. to Dr. Mortimer; wherein he inclosed the foregoing Account of the Plica Polonica; together with an Article from the Breslaw Sammlung von Natur- und Medicin, &c. Geschichten upon the same Subject, translated from the High-Dutch by Dr. Mortimer, R.S.Secr. SIR, January 20th, 1732. * * * THE PLICA has been always related, and thought to be a Distemper, and to proceed from a Fever or Convulsions; but for my Part, from the best Information I could get concerning it, I think think it a Product of Nastiness, by not combing their Hair, nor washing their Heads; for if it were a real Distemper, the People of Fashion could no more be free from it than the ordinary People, among whom (i.e. the ordinary and poor) it only happens. This is confirmed by an inquisitive Person, (a Correspondent of Mr. Job. Henry Lincke, F.R.S. of Lipstick,) who sent the following Article to the Society of Breslau, in whose Transactions, entitled, Sammlung von Natur- &c. Anno 1724, Artic. 17, Mensis Augusto, p. 126, it is inserted to this Purpose. "The great Multitude of People in Poland, who are troubled with this Plica, first made me reflect, whether it were a real Disease or no? I am now convinced, that their swinish Way of living, and the common Opinion so deeply rooted in the Generality of People, that this Lock of Hair cannot be taken off without Danger of their Lives, have contributed more to this Complaint than any real Indisposition of Body; considering that it is the middling or poor People, who are troubled with it; whom then one cannot look on without Horror: But no German, of whom there are great Numbers, who live in that Country, ever had any such thing grow. Many of them, who are married to Women of Polish Birth, are scarce able to persuade their Wives not to train up their Children to this Nastiness. Not long since I saw a Fellow in the Church, who had about seventy of such Locks hanging down from his Head, which were were as hard twisted, as so many Penny Cords; that one might easily have taken his for a Medusa's Head (and who knows, but that in ancient Times some such Locks as these might have given Rise to the Poetical Fiction of Snakes growing on the Head instead of Hair? Be that as it will, this is certain, it is a most odious Sight to look on. IX. An Account of an unusual Agitation in the Magnetical Needle, observed to last for some Time, in a Voyage from Maryland, by Capt. Walter Hoxton; communicated in a Letter to David Papillon, Esq; F. R. S. On the second of September, 1724, a little after Noon, being in Latitude $41^\circ 10'$ N. and Difference of Longitude from Cape Henry in Virginia about $28^\circ 00'$ E. the Weather fair, a moderate Gale, and smooth Sea, my Mate, who was on the Deck, came and told me, that the Compass traversed so much that he could not possibly steer by it: Whereupon I went up, and after trying it in several Parts of the Ship, found what he said to be true. I then had all my Compasses brought up, and placed in different Parts of the Ship, and in Places most remote from Iron, and, to my great Surprize, found them all in the same Condition; so that we could not steer by any of them. I then new touched some of them with a Loadstone, which