Silk Manufacture. 81 



great quantity of fruit. The best reason, however, if it be 

 correct, that has been given for preferring it, is, that the silk 

 of worms which feed upon its leaves is finer than where other 

 kinds are substituted. Count Dandolo has, indeed, found, 

 that the quality of the filament does not solely depend upon 

 the food of the insect, but is also influenced by the degree 

 of temperature in which it is reared. 



'In cold climates, the black thrives better than the white mul- 

 berry. It likewise bears double the quantity of leaves suitable 

 for food. In Persia the silk worm is nourished altogether by 

 leaves of the black species. In Granada, where silk of excel- 

 lent quality is produced, the same system is followed. Swin- 

 burne, who travelled in Calabria in 1784, relates that the red 

 species was there generally preferred, because the leaves, not 

 appearing until ten or fourteen days later than those of the 

 white mulberry, are therefore less subject to injury by frost. 

 This reason for its preference is in other climates assigned 

 as the cause of its rejection. 



'The roots of the mulberry tree strike very deep into the 

 ground, so that the surface not being impoverished as it is by 

 many trees, whose roots are found more in the upper soil, 

 other kinds of cultivation may be prosecuted around it. 

 Neither its shade, nor the dropping of rain from its leaves, is 

 considered prejudicial to plants growing beneath. 



'Moist lands in valleys and near rivers induce a very rapid 

 growth in the trees ; but their leaves contain, in such situa- 

 tions, too much watery matter, and, though eaten voraciously, 

 are hurtful to the worms from their comparative want of 

 nourishment. The labors of the insects are also delayed, and 

 the quality of their produce injured by the weakness of con- 

 stitution resulting from this cause. 



' Trees in dry soils give fewer leaves, but any deficiency in 

 their quantity is amply compensated by the greater nutriment 

 which they afford, and, as a necessary consequnece, by the 

 superior quality of the silk produce. 



' It is remarked by Mayet, that the quality of the silk de- 

 pends upon that of the mulberry leaves consumed, " which 

 are then to be considered as being only a mine worked by 

 the worms ; and this mine is more or less proper to furnish the 

 fine substance, according to the soil and climate." 



' The mulberry tree is readily raised, either by cuttings, by 

 layers, or by seed. In countries where the seed must be saved 

 until the favorable season for sowing it shall come round, the 

 process is both troublesome and difficult. Pullein, who 

 wrote in the year 1758, gives very elaborate directions, which 

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