80 Miscellaneous. 



position just below the eye-piece. With this arrangement, using an 

 eighth-inch objective made by J. & W. Grunow, I was able to see 

 three sets of lines on the Navicula angulata clearly defined ; and 

 with a good light I could also distinctly see the six sides of the little 

 hexagons on the same specimens. These phsenomena can be seen 

 with either of the three eye-pieces belonging to the microscope ; but 

 the six sides of the hexagons are best seen with No. 2 or No. 3 eye- 

 piece. Taking away the compensating prism of plain Iceland spar, 

 and with the same arrangement in every other respect, at the utmost 

 only two sets of lines were seen, and the hexagons appeared only as 

 black dots, the form of which could not be distinguished. These 

 facts prove conclusively, as I think, the great value of the compen- 

 sating prism here described, which has never before been applied to 

 the microscope, so far as my knowledge extends. — Sillimans Journal, 

 November 1858. 



On the Introduction of Bombyx Cynthia into France. 

 By M. Guerin-Meneville. 



One of the most active and distinguished of the members of the 

 Society of Acclimation, M. Guerin-Meneville, who has been especially 

 interested in the introduction of new silk-worms, has just succeeded 

 in acclimatizing in France a new silk-worm from China, where it lives 

 on the Varnish- tree (Ailanthus glandulosus) . The species is the true 

 Bombyx Cynthia of Drury (1773), figured for the first time by 

 Daubenton, jun., in his coloured plates, which were published between 

 17C0 and 1765, and raised for some centuries in China, where its 

 silk clothes the people. Roxburgh, in 1804, supposed the Eria 

 which is raised in British India to be the same ; and this confusion 

 has continued till recently, — so that the Eria (or * Arrindy-arria,' as it 

 is called in Hindostan) has gone by the nam.e of Bombyx Cynthia, 

 The Eria is a different species, living on the Ricinus. 



The study of the species by Guerin-Meneville has brought to light 

 differences between the two in the cocoons and the habits of the worms. 

 The cocoons carded give an excellent flock of silk, which is used in 

 China and Bengal for very firm tissues. The colour of the silk is a 

 fine flax-grey ; and clothes made of it are not injured by the rain, or 

 oil, and wear long. 



Now that the introduction of the silk-worm is accomplished, atten- 

 tion is turned to the extension of it industrially. Guerin-Meneville 

 proposes for this end the making of plantations of Ailanthus^ a tree 

 that grows easily on poor soil, then to place upon them in spring 

 the worms that were hatched in the month of May, and let them eat 

 the leaves. Care should be taken to preserve them from the birds, 

 which is easily done by an invalid workman incapable of other work, 

 as has been the custom for centuries in China. At the end of June 

 the first crop may be gathered, and a second in August. The cocoons 

 for reproduction should be preserved until the next May, which re- 

 quires, as with the silk-worm of the Ricinus and the Bipsacus Fullo- 

 num, special care in the winter. — Silliman' s Journal, November 1858. 



