A Confirmation of What Was Formerly Printed in Numb. 50. of these Tracts, about the Manner of Spiders Projecting Their Threds; Communicated by Mr. John Wray, to the Publisher

Concerning the manner of Spiders projecting their threads, I received the following account from Dr. Huse, from whom (to do him right) I must acknowledge, I had the first notice of this particular, which was not long after communicated to me by another Ingenious Friend, whose Letter I formerly sent you to be imparted to the R. Society. Nor is it any great wonder, that Inquisitive persons, applying themselves to observe and consider the same subjects, should make the same discoveries. I have (saith he) seen them shoot their webbs three yards long before they begin to sayl; and then they will (as it were) fly away incredibly swift. Which phenomenon doth somewhat puzzle me, seeing oftentimes the Air doth not move a quarter so fast as they seem to fly. Mostly they project their threads single, without dividing or forking at all to be seen in them: Sometimes they will shoot the thread upward, and will mount up with it in a line almost perpendicular; and at other times, they project it in a line parallel to the plain of the Horizon; as you may often see by their threads that run from one tree to another; and likewise in Chambers from one wall to another. I confess, this Observation at first made me think, that they could fly, because I could not conceive, how a thread could be drawn so parallel to the Horizon between two Walls or Trees, as above-said, unless the Spider flew through the Air in a straight line. The way of forking their threads is expressed by the following Figure. (See Tab. 2. Fig. VII.) What reason should be given of this dividing, I know not, except that their threads being thus winged, become better able to sustain them in the Air. They They will often fasten their threads in several places to the things, they creep upon: The manner is, by beating their tayles against them as they creep along; which may be understood by this line. See Tab. 2. Fig. VIII. By this frequent beating in of their thread among the asperities of the place, where they creep, they either secure it against the wind, that it be not easily blown away; or else, whilst they hang by it, if one stick breaks, another holds fast; so that they do not fall to the ground. A Note Concerning the next foregoing Relation. After we had received the precedent Confirmation touching the first observer of the Darting of Spiders, there came to hand a Letter from that Inquisitive Gentleman, Mr. Martin Lister, intimating, That if we were not yet fully satisfied about that matter, he had this further to say; that Mr. Wray knew nothing of his knowing it, no more than he (Mr. Lister) knew, that either he or any body else knew it, untill such time, as he occasionally sent him a Catalogue of our English Spiders: Upon which subject, in the next Letter, Mr. Wray put this among other questions to Mr. Lister, whether he had observed the Darting of Spiders: To which he answered in the affirmative, relating to him many other circumstances not observed by him before, so that he was desired by Mr. Wray, to draw up his notes, and suffer him to present them to the R. Society: which he did. After which, the said Notes were also publish'd, in Numb. 50. of these Books. Whence it appears, that this Observation is as well Mr. Lister's, as Dr. Hulfe's (as is also acknowledged in the beginning of the precedent Account;) though it be true also, that when it was written and sent by the former of those two Gentlemen, it was not then a thing altogether unknown to Mr. Wray, but confirmed and enlarged by Mr. Lister's own Obser- Observations. Which was thought fit to add here, that nothing might be detracted from Mr. Lister for permitting his Notes in the lately mention'd Tract to be published as his own, which really they are. An Accompt of some Books. I. DE CORPORUM AFFECTIONIBUS cum MANIFESTIS tum OCCULTIS, Libri Duo: Seu Promota per Experimenta Philosophiae Specimen, Auth. J. B. Du Hamel, Ecclesiae Bajocensis Cancellario. Parisiis, 1670. in 12°. The Learned Author of this Treatise having represented in the Preface, that the Grecian Philosophy concerning Nature, hath been so far from being able to grow up any thing considerably, that by the more Generous and the more Intelligent men of this Age, it is esteem'd rather to have degenerated and decayed; giveth here a specimen of Natural Philosophy improved and advanced by Observations and Experiments; not only endeavouring to explicate, from the Principles of the Modern Philosophers, the Qualities and Powers of Bodies, but also giving an Accompt of the more notable Experiments, made in this Age in divers places, as England, France, Italy, Germany, &c. In the Performance of which he treats, In his First Book, of the Origine and Nature of Qualities in General; then, of Heat and Cold; of Fluidity and Firmness and other Tactile Qualities; of Tasts, Smells, Sounds, Light, and Colours. In the Second, Of Medicaments in General; then, of the Vertue and Use of Preparing, Alterative, Purgative, and Topical Medicines; as also of Poisons and Antidotes. In the same, he proceeds to consider Magnetisme, Electricity, Gravity in general, and the Accelerated motion of Heavy Bodies: Concluding the whole with the consideration of Liberated Liquors, and the Weight of the Air.