5*70 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



PKEPAEATION OF. FRENCH CHALK. 



The substance generally known as Prench chalk, used by 

 tailors for making marks upon cloth, is manufactured by rub- 

 bing up ultramarine, ochre, etc. (according to the color de- 

 sired), with pipe-clay softened with Avater. The mixture is 

 then poured into moulds, and dried in a slightly heated room. 

 21 A, December, 181 2, 1142, 



YELLOW COLOK OF SILK. 



Pfeiifer informs us that the yellow color of silk is a more 

 or less altered chlorophyl, which has been deprived of its 

 blue color. He succeeded in extracting uncolored chloro- 

 phyl from the raw silk, Avhich, when heated with ether con- 

 taining hydrochloric acid, could be again divided into the 

 blue and yellow constituents. 13 A, February 15, 1873, 70. 



SILK W^ITHOUT THE SILK-W^ORM. 



It is said that the Italian manufacturer, Marasi, has patent- 

 ed a very simple process for the joroduction of silk from the 

 bark of the mulberry- tree, in Avhich chemical agents pre- 

 viously unsuccessfully employed, such as soda, lime, etc., are 

 dispensed with. Fibres are said to be obtained entirely free 

 from parenchyma, and resembling in color, appearance, fine- 

 ness, and strength a specimen of Moorish silk. Similar state- 

 ments have, however, heretofore proved unfounded. 8 C, 

 January IQ, 181 Z, 22. 



IMPROVEMEXTS IN THE MANUFACTURE OF SILK. 



In an account of the progress of silk manufacture, by Al- 

 can, the two following items seem of j^articular interest : 



It occurred to Alcan to simplify the process for killing 

 the worms in the silk cocoons, by employing a volatile sub- 

 stance (camphor) instead of steam, which is generally em- 

 ployed in European countries, at a risk of loss by subsequent 

 rotting, etc., unless the cocoons are carefully and thoroughly 

 dried. 



About 40 pounds of cocoons were transported from South- 

 ern France to Paris, in a box in which a small quantity of 



