Silkworm from Japan. 421 
. 
place the ends of the bough in a potato instead of a bottle, having 
fixed it to a box perforated with holes; and it is as well to choose 
the time of their first or second moult. The branches should be 
well fixed to the sides of the box, and when they moult they will 
be at their journey’s end. Cocoons may be transmitted, twenty 
days after they have been commenced, in perforated shallow 
boxes. 
The cocoon of B. Yamamai weighs 7 to 8 grammes,* where- 
as the cocoon of B. Mori weighs 24 to 3 grammes.t The 
silken material is in the same proportion, viz. 70 to 80 centi- 
grammes ;¢ that of the mulberry, 25 to 35 centigrammes.§ To 
estimate the resultant silk in weight from a given weight of 
cocoons, it is customary to allow 12 lbs. of cocoons to make 
1 Ib. of silk, allowing for waste, &c. The Yamamai cocoon will 
have a slight advantage in this over the mulberry cocoon, owing 
to its greater size and less waste. It is wound as easily as that of 
the mulberry cocoon, from end to end in a continuous thread, 
when placed in boiling water. ‘There are two qualities of silk, the 
exterior layers of the cocoon being stouter and of a greenish 
yellow tint, and the interior of a fine texture and white colour; 
hence the winding is divided into two operations, so as to preserve 
the two qualities distinct. Regarding the quality of the silk, 
Mons. Gelot pronounced the following opinion at the International 
Exhibition of Insects at Paris in 1865.|| ‘The silk of the Bombyx 
Yamamai seems to me to occupy, after that of the mulberry 
worm, the highest rank. It is perhaps a trifle less fine, but is 
quite as brilliant as that silk. I believe in many cases it might be 
employed instead of it; and that if we succeed in acclimatizing its 
production on a large scale, it might make up for our deficiency in 
the production of mulberry silk. The clear green tint which it natu- 
rally possesses is no obstacle to the various shades of dye, for it 
disappears with washing and becomes white. The rapid develop- 
ment of this valuable branch of industry cannot be too highly en- 
couraged.” Elsewhere §] we read: Several bales of Yamamai 
silk have been purchased at Yokohama, Japan, at 550 piastres the 
* About 4 oz. 
+ About } oz. 
t~ 10—12 grains. 
§ 4—6 grains. 
|| Vide Revue de Sériciculture, 1865, p. 188. 
q Revue de Sériciculture, 1865, p. 39. 
GG 2 
