426 PHILOSOPHICAL TRANSACTIONS. [aNNO I/IQ. 



the flat eye serving as a common eye armed with a concave lens. I have so 

 fixed the telescope, as to make a presbyta read a small print at a great distance. 



New and accurate Tables for readily computing the Eclipses of Jupiter's Jlrst 

 Satellite, by Addition only. By the Rev. Mr. James Pound, F. R. S. 

 N°36l, p. 1021. 



The tables of this satellite are here omitted, being superseded by other 

 more modern tables of greater accuracy, in the present treatises on astronomy. 



Account of several Experiments and Observations on the Production of Silk 

 Wormst and of their Silk in England. By Mr. Henry Barham, F. R. S. 

 N° 362, p. 1036. 



Experiments made in Chelsea Park, in the months of May, June, and 

 July, 1719- 



April 27, I received a small parcel of silk-worm's eggs from Languedoc. 



May 6, early in the morning I found them hatched of themselves, the wind 

 shifting in the night from east-northerly to the west-southerly, changing the 

 air of a sudden to warm, two days before the change of the moon. 



After feeding and managing them according to art, through the whole course 

 of their four sicknesses, they were come to their state of perfection, being then 

 as thick as a man's little finger, and from 4 to 5 inches long, of a yellowish 

 colour, and when held against the light, they might be seen through as you 

 may an egg, being of the same colour and consistence, filled with the matter 

 that forms the silk. This is a certain sign that they will begin to spin in 24 

 hcKirs, or less. They then forsake their food, being very voracious before, and 

 hunt about for a convenient place to fix their first hold- fasts, for supporting the 

 balls or cones they are to make, which they do in a very surprising and mathe- 

 matical manner, by means of a gammy substance that ties all together; and 

 when the loose furzy substance is taken off, and some of the silk is wound off^, 

 the remainder is so smooth and compact, shining like sattin, that they are used 

 for artificial flowers, and esteemed the best of any thing yet known for that 

 purpose. I weighed many hundreds of these silk-balls or cones, which I 

 found to weigh from 35 to 40 grains, with their aurelias or crysalids within 

 them. 



June 27, they began to spin, having been hatched 7 weeks and 3 days; and 

 in 4 or 5 days finished their laborious and curious work; but their balls were not 

 fit to be removed till 8 or 10 days. 



