| Description | ' The President in the Chair
The minutes being read; Dr Ling and Captain Robinson were permitted to be present.
Dr Steigerthall delivered a Paper of Mr Kleifler's in Latine containing a description of several remarkable things found upon digging a deep mote or Trench by order of his presents Majesty of Great Britain; which was read. In which he describes the dirrerenct sorts of arth, Stones, Sand clay, found at different depths in digging this Trench and gives an Account of various bodies dug up at freat depths as well abumal as vegetable. Several Treees the Beach and Oak, Stage horns, shells of fish among which were the pearl fish, several works of art among which were divers Instruments of war, some urns found among the rubbish of old buildings. From which circumstances joined with other reasons concludes this to be the ancient Tower of Limmer which he supposes might have been destroyed by Some inundation.
Mr Keisler had the thanks of the Society.
Sir Hans Sloane propounded Mr Keisler as a fit person to be elected a Member of the Society. Mr Keisler made the Society a present of his Book intitled Exercitatio Historia Philologica de Dea Nehellenia numine veteram Wallachrorum Topico. For which he wa also ordered the thanks of the Society.
Two manuscripts relating to some improvements designed in the pracise of the Arts of Navigation and written by one Mr Roe were produced before the Society to be perused.
The first was an Attempt to measure time by hour Glasses made with quicksilver and enclosed in an exhausted Receiver which was proposed as a more exact and perfect method to measure time at Sea than the common way by Land Glasses.
The other contained the Description of New Sea Quadrant to take Altitude in hazy Weather when the Horison cant be discerned by a Quick-Silver Level made in the form of hollow circular Tube of Glass fitted to the limb of the Quadrant.
Mr Desaguliers delivered an Account of some experiments tried upon several bodies with Monsieur Villet'sBurning Concave in June 1718 by the reverend Dr Mardies and himself together with the Bodies them selves which he presented to the Society.
The Mirroir is 47 47 inches wide, the radius of concavity 76 Inches, the focal distance 38 Inches from the ventea of the Glass. The metal of which the miroir is made is a mixture of Copper, Tin and Tin Glass it casts a yellow reflection.
The times were measured by a half Second Pendulum the Experiments were made between 9 and 12 in the norning and wee as follows;
No. 1 A red piece of Roman patera began to melt in 3 seconds was ready to drop in a 100 secnds
2. Another black peice melted at 4 and was ready to drop in 64 seconds
3. Chalk taken out of aqn Echinus Spatagus filled with chalk only fled away in 23 seconds
4. A fossile Shell calcined in 7 seconds and did no more in 64 seconds
5. A piece of Pompeys's Pillar at Alexandria was vitrified in the black part in 50 seconds and in the white part in 54
6. Copper Oar [?] that had no metal visible in it vitrified in 8 seconds
7. Slag, or Cinder of the ancient Iron-work said to have been wrought by the Saxons ready to run in 29 seconds, 8 1/2
Here the glass growing hott burned with much less force.
8. Iron Oar fled at fife but melted in 24 seconds
9. Talc began to calcine in 40 seconds and held in the focus 64"
10. Calculus humanus was calcined 2 seconds and dropt off in 60
11. An anonymous fifth's tooth melted 33.5 seconds
12. The Asbestor seemed condensed a little in 28 seconds. It was now something cloudy.
Mr Villet says the glass usually calcines it.
13. A Golden Marchasite broke to pieces and began to melt in 30 seconcds
14. A Silver Sixpence melted in 7 1/2 seconds
15. King William's Copper halfpenny melted in 16 seconds and ran in 34
17. Tin melted in 3 seconds
18. Cast iron in 16 seconds
19. Slate melted in 3 seconds had a hole in item 6
20. Thin tile melted in 4 seconds, had a hole and was vitrified in 80
21. Bone calcined in 4 Seconds and vitrified in 33
An Emerald was melted into a substance like a Turcoise Stone
A Diamond weighing 4 grains lost 7/8 of its weight. ' |