410 INSECTS. 



by far too fine for any purpose in our manufactories, while that of 

 another class is too coarse. 



Several very laudable attempts have been made, but hitherto 

 without any considerable degree of success, to rear the silk worm 

 in Britain. The public have been informed, by a manufacturer, 

 of Paisley, of his havi ig prepared a web entirely of the silk 

 produced by worms of his own rearing. And in the Transactions 

 of the Society for the encouragement of arts, manufactures, and 

 commerce, a number of very useful experiments are recorded with 

 regard to the food and management of these insects. 



Probably the want of a sufficient number of mulberry trees has 

 hitherto rendered ineffectual the efforts of our countrymen to 

 introduce and rear any considerable quantity of silk- worms. From 

 the attempts that have already been made, it appears, that the 

 white mulberry is preferable to the black, in feeding ; and that 

 the latter is to be preferred to the lettuce. Twelve cocoons, the 

 produce of worms fed upon the white mulberry, weighed seven 

 penny.weights two grains, while an equal number of those that 

 had been fed upon the black mulberry weighed only six penny- 

 weights three grains ; six penny-weights were obtained from the 

 same number of worms fed upon common lettuce. 



Endeavours to produce raw silk in our own country seem the 

 more worthy of encouragement, as we appear to possess some 

 advantages of which Italy and many other silk countries are desti- 

 tute. In Italy the chrysalids so soon come to life, that it is neces. 

 sary to destroy them, lest, by eating their way out, they should 

 injure the silk. In order to effect this, they are collected and 

 placed in heated ovens, where again the silk, without singular 

 caution, is apt to be damaged. In our own climate, where every 

 progression of the insect tribe is slower, there is sufficient time to 

 wind off the silk without killing the chrysalis. 



But beside the injur) tha' may be done to the silk in Italy, from 

 the length of time which it is necessary to keep the chrysalites in 

 these ovens, they are there obliged to suffer the moth to eat its way 

 out of the largest cones, in order to have eggs from the most 

 vigorous and healthy. Hence they lose all the silk of these cones, 

 which, in our own country, might be gathered while the moths are 

 preserved. Thus we seem to possess two striking advantages, 



