Intelligence and Miscellanies. 391 



maline are more electric by heat than the entire tourmaline, 

 and that when the latter is very long, it cannot acquire the 

 pyro-electric virtue. We were then ignorant that M. Brews- 

 ter had made analagous experiments under date of Aug. 2d, 

 1?'.24. The following are the expressions of the Scotch phi- 

 losvtpher: "In examining the electricity of the tourmaline. 

 I have found that it is much more easily observed with a small 

 fragment broken from any part of the prism. The experi- 

 ment succeeds better when the fragment has its faces perpen- 

 dicular to the axis of the crystal. When such a fragment is 

 placed on a glass and heated to a boiling temperature, the 

 fragment adheres to the glass with so much force that on in- 

 ve ting it, the fragment remains suspended during six or 

 eight hours. In this manner, pieces of considerable thick- 

 ness and surface are capable of supporting their own 

 weight. He adds further, that the dust of the tourmaline 

 adheres in a mass when heated on a glass, and stirred with a 

 dry substance. — Ferussac's Bulletin, J^ov. 1828, 



46. JVeti? method of preserving Crystallized Salts j hy M. 

 Deuchar. — Agreeably to the statement of the author, salts 

 may be prevented from efflorescing or burning liquid, by 

 charging the air of the vessel in which they are kept with the 

 vapor of the spirits of turpentine. It is sufficient for this 

 purpose to pour a very small quantity on the bottom of the 

 vessel. — Ibid. 



47. Conversion of potatoe jlour into mitritious bread. — M. 

 Darcet proposes, in order to render the bread of potatoe flour 

 as palatable and nutritious as that of wheat, that some animal 

 substance should be added to the mixtures, and this he finds 

 may be gelatine, or caseous matter. In 1821 he proposed 

 to add gelatine to wheat flour for the purpose of making a 

 more nutritious biscuit for the use of the navy, and some of 

 these were prepared under his direction for the voyage of 

 circumnavigation now under the command of M. De Durville. 

 The wheat flour used by the bakers of Paris, contains about, 



Water, - - - - - 10 



Gluten, - . - - - 10 



Starch, - - - - - 73 



Saccharine matter, - . . , - 4 



Gummo-glutinous matters, - - - 3 



100 



