On, the Structure of Rice Paper. 133 



£. Euchroite contains a considerable proportion of water 

 &nd copper. An exact indication of the rest of the ingre- 

 dients in its remarkable chemical composition, will be given 

 in the next number of this Journal, Dr. Turner having, at 

 my request^ kindly undertaken an examination of it* 



Aht. XXIII.— CONTRIBUTIONS TO POPULAR SCIENCE. 

 No. 111. Ori the Structure of Rice Paper \ * 



The substance commonly known by the name of Rice Pa- 

 per is brought from China in small pieces, about two inches 

 square, and tinged with various colours* It has been for 

 some time used as an excellent substitute for drawing papery 

 in the representation of richly coloured insects, and other ob- 

 jects of natural history, and has been employed in this city 

 with still more success in the manufacture of artificial flowers. 



Although rice paper has a general resemblance to a sub- 

 stance formed by art, yet a very slight examination of it with 

 the miscroscope is sufficient to indicate a vegetable organiza- 

 tion. In order to observe and trace the nature of its struc- 

 ture, it was necessary to give it some degree of transparency ; 

 and I expected to accomplish this by the usual process of im- 

 mersing it in zvater or in oil of the same refractive power. 

 This operation, however, instead of increasing the transpa- 

 rency rendered the film more opaque, and suggested the pro* 

 bability that, like Tabasheer, it was filled with air ; and that 

 the augmentation of its opacity arose, as in the case of that 

 fiilicious concretionj from the partial absorption of the fluid. 



In order to expel the air from the cells in which it seemed 

 to be lodged, I exposed a piece of the rice paper to the influ- 

 ence of boiling olive oil. The heat immediately drove the 

 air in small bubbles from the cells near the margin ; but it 

 was with some difficulty that it was forced to quit the interior 



• From an unpublished MS. by Dr. Brewster, read before tho Royal Societ/ 

 of Edinburgh, on the 4th March, 1822. 



