"870 JPHILOSOPHICAL TRANSACTIONS. [aNNO 16Q3' 



to them, in half a minute they will begin to move themselves again, and by 

 degrees begin to swim, faintly and feebly at first, and then, recovering their 

 strength again, perform their brisk motions as vigorous as ever. These ani- 

 malcula chuse for the most part the top of the liquor, probably for the sake of 

 the air. 



Now as a further testimony that they are animalcules, which some doubt of, 

 I have noted the following observations : If you take a fine needle, and put the 

 point into spirit of vitriol, and prick a small drop with it, these minute animals 

 will, from moving briskly about, spread themselves flat, and appear to fall down 

 dead. Dissolved salt produces the same effect upon them, with this difference, 

 that instead of becoming flat, as those with spirit of vitriol did, they shrink 

 into an oblong round form. Tincture of salt of tartar, used the same way, 

 kills them more immediately ; but yet they will seem to be first so sick, as 

 appears by convulsive motions, that they grow faint and languid apace, and then 

 fall down dead to the bottom, without any change in their shape. Ink kills 

 them as soon as spirit of vitriol, but makes them seem to shrink various ways. 

 Fresh blood kills them almost as soon as spirit of vitriol. Urine kills them also 

 in a little time, though not so soon. Sugar, dissolved like salt, kills them also 

 if used in the same manner ; and with it some die flat, and othere round. Sack 

 will kill them, but not so speedily as the others liquors. 



The Manner of making and tempering Steel, with a Conjecture at the Method the 

 Ancients used to steel their Picks, for cutting Porhyry. By Martin Lister, 

 M.D. and S.R.S. W 203, p. 865. 



In the Philosophical Transactions, N" 93,* amongst other desiderata and 

 queries, are these ; to endeavour to retrieve the art of hardening and tempering 

 steel for cutting porphyry, &c. We know not which way to rough-hew stones 

 of that untractable hardness. Those stupendous monuments of antiquity, the 

 Egyptian obelisks, are of porphyry, and most of them curiously carved with a 

 vast number of figures, which was one way of writing among the ancient Egyp- 

 tians. These figures show the facility that nation had of engraving in porphyry ; 

 a stone which no tool will now touch, nor any thing less than emery or diamond 

 powder affect. Mr. Ray assures us, that all the obelisks at Rome, engraven 

 with hieroglyphics, are of the same kind of stone, viz. a marble -|- of a mixed 

 colour, red and white, very hard, and without suffering the least injury by the 

 weather for many ages. There is certainly something lost in this age, as to the 

 manner of steeling tools. As for the moderns, there is great abuse in this 



* Vol. ii. pp. 59 and 60 of these Abridgments. \ Not marble, but either porphyry or red granite. 



