ON THE CULTURE OF SILK. 79 



geously. No buildings constructed expressly for the purpose 

 will be necessary. '' I have reai'ed them with success, says 

 Cobb in his Manual, recently published agreeably to a resolve 

 of the Commonwealth, in a barn, in my cellar kitchen, and 

 other rooms of my dwelling house, and in the lower story of the 

 Tremont House in Boston. It was found in France that the 

 cocoons brought to market by the peasants, raised in hovels so 

 full of cracks as easily to be seen through and to admit the air 

 freely, were richer and heavier than those reared in palaces and 

 in the confined rooms of dwellings in cities." A well lighted 

 dry, warm, airy room, is, however, to be preferred. An open fire 

 place is desirable — for it not only serves at all times as a good 

 ventilator, but in cold days, and even during warm, calm, sultry 

 weather, a little fire may be occasionally kindled with advantage — 

 on cold days to warm the room, and on warm, sultry occasions 

 to remove the stagnant air and excessive moisture. In Europe 

 their laboratories are furnished with stoves and the heat regulated 

 by a thermometer. This, Cobb and others who have had much 

 experience in rearing silk worms in this country, consider unne- 

 cessary. A uniform temperature of about 73 degrees of Fahren- 

 heit is thought to be most favorable to perfect success. Greater 

 heat, especially if accompanied with a damp, sultry atmosphere, 

 produces sickness, and if it occurs near the completion of their 

 growth a coarser product. The finest and most valuable silk, as 

 well as the largest quantity, is produced by the most healthy 

 worms, during fine weather of the temperature above named. 

 Hence a climate as cold at least as ours, we have been told by a 

 silk manufacturer from Spain, is m.ost favorable to the production 

 of fine silk. The inferiority of Spanish silk to that of some other 

 parts of Europe he attributed to the greater warmth of the 

 Spanish climate. 



Natural History of the Silk Worm. — The phalena moth or 

 silk butterfly is about an inch long and nearly an inch and a half 

 between the extremities of its wings when extended. The body 

 is obscurely white and thickly covered with short hairs — it has 

 two antennae or feelers, and four transparent wings of the color 

 of the body, flat and incapable of dilatation or contraction ; it 



