32 PHILOSOPHICAL TRANSACTIONS. [aNNO 1605. 



much quickness, and draw it so subtle and so long, that, without an hyperbole, 

 the end or thread of every case may have two leagues in length.* He adver- 

 tises, that they must by no means be interrupted in their work, to the end, 

 that all the silk they have in their bellies may come out. 



Some eight days after they have finished their work, as many of the best 

 cases as are to serve for seed, viz. the first done, the hardest, the reddest and 

 best coloured, must be chosen, and put apart ; and all diligence is to be used 

 to wind off the silk with as much speed as may be, especially if the worms 

 have nimbly dispatched their work. 



Here he spends a good part of his book in giving very particular instruc- 

 tions concerning the way of winding off the silk, setting also down the form 

 of the oven and instruments necessary for that work, which is the painfulest 

 and nicest of all the rest. 



Touching their generation, he prescribes that there be chosen as many male 

 as female cases (which are discerned by this, that the males are more pointed at 

 both ends of the cases, and the females more obtuse on the ends, and bigger- 

 bellied), and that care be had, that no cases be taken, but such wherein the 

 worms are heard rolling ; which done, and they being come forth in the form 

 of butterflies, having four wings, six feet, two horns, and two very black eyes, 

 and put in a convenient place, the males fluttering with their wings, will join 

 and couple with the females, after that these have first purged themselves of a 

 kind of reddish humour: they are to be left from morning (which is the or- 

 dinary time of their coming forth) till evening, and then the females are to be 

 gently pulled away, whereupon they will lay their eggs ; but the males are then 

 thro\vn away as useless. 



Enquiries concerning Agriculture. N° 5, p. 91- 



The Royal Society, in prosecuting the improvements in natural knowledge, 

 have it in design to collect histories of nature and arts ; and for that purpose 

 have already, according to the several inclinations and studies of their members, 

 divided themselves into divers committees, to execute the said design. Those 

 gentlemen who constitute the committee for agriculture, and the history and 



* Monsieur Isnard's computation seems rather to border on the extravagant. The length indeed 

 may be supposed, to differ considerably in tlie different silk-balls, but, in general, will be found far 

 short of that stated by Isnard. According to Boyle, as quoted by Derham, a lady, on making the 

 experiment, found the length of a ball to be considerably more than tliree hundred yards, though 

 the weight was only two grains and a half. The Abbe Le Pluche informs us, tliat of two balls one 

 measured 9Q4 feet, and the other 930. It may be proper to add, that the silk throughout its whole 

 kngth is double, or composed of two conjoined or agglutinated filaments. 



