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its Spherical Figure. It may be pollisht upon the same Plain applying to it the Paper smoothly cemented on. But here it is to be consider'd, that the polishing, practised with this Instrument, is very long and tedious; so that O would advise, after the Glass is wrought to the perfect figure on the Plain, to make * These Gutters the Author describes in another part oi this Book; where he saith, That there must be a Polisher made in the form of a Gutter, excavated its whole length; which may also be hollow'd Spherical by means of a wooden Mould, turn'd of a Spherical figure by a Gage, fixt on a Mandril, and made to turn round: which he saith, may also be better perform'd upon certain square Stones of a peculiar kind, which, when he first attempted the working of Glasses, he made great use of. use of certain Gutters* proportionable to the Sphere, whole Semi-diameter is represented by the length of the Pole above-mentioned; using for the rest, the rules known and observed in the grinding of Convex Glasses.

So far this Author of this contrivance, which though it be Ingenious and Mathematical, yet is it conceived by skilful and considering Artists, that it will be very difficult to put it into practise with Glasses of any considerable length; it being also much doubted, whether the Author himself hath ever used it, or seen it used in long Glasses.

 

An Extract

Out of the Italian Giornale de Letterati, about two considerable Experiments of the Transfusion of the Blood.

ANno 1667, May 8. Here was made in Bononia at the house of Signior Cassini this Experiment, viz. There was open'd the carotid Artery of a Lamb, when the blond was let run as long as it could, into the right branch of the jugular Vein of another Lamb, from which there had before been drawn so much bloud, as was judged, it could be supplyed with from a Lamb of the like bigness, whose bloud should be let out till it dyed. After this, there were made two ligatures pretty near to one another, in the vein of the Lamb, that had received the bloud; and this vein was quite cut thorow between the two ligatures, to see what would happen thereupon. This done, the Lamb was untyed, which without any appearance of feebleness, went about, following those that had made the operation, It lived a long