462 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



excellent results, and consists simply in immersing them for 

 a moment in melted paraffine, drawing them out quickly, and 

 shaking them gently, so as to remove the excess. For this 

 treatment it is necessary that the flowers be fresh plucked, 

 and entirely free from drops of rain or dew. The paraffine 

 must be heated only enough to be liquid, as a greater degree 

 of temperature would injure the flowers. The flowers are to 

 be immersed one by one, and shaken about somewhat, so as 

 to prevent the adhesion of bubbles of air to the surface. 

 Such portions of the flowers as can not be easily preserved 

 are to be trimmed away, before immersion, with scissors. 

 6 B, January 1 8, 1 872, 28. 



PREVENTION OF " WIGGLERS" IN WATER. 



A writer in the " Scientific American," who has been much 

 troubled by the occurrence of what he calls " wigglers" in 

 his rain-water casks, states that by pouring a thin film of 

 kerosene oil on the surface, and stirring it a little, so as to 

 make the film of oil entirely continuous, the difficulty will 

 be entirely cured. 



These animals consist principally of the larvae of the raus- 

 quito and other diptera, which are developed from eggs laid 

 by the parent on the surface of the water. Contact with the 

 oil kills the egg at once ; and the larvae, on arriving at the 

 surface for the purpose of completing their transformation, 

 are also killed. It is necessarv to draw the water off from 



mi 



below through a spigot, in order to prevent any disagree- 

 able taste or odor. 6 D, August 10, 1872, 84. 



TEST OF ALUM, ETC., IN BREAD. 



A test for the presence of alum in flour used for bread 

 consists in applying a drop of alcoholic extract of logwood. 

 This, upon pure bread or flour, produces, according to Biich- 

 ner, a yellowish-brown color; wirile, if alum be present to 

 the extent of one or two per cent., a gray blue or gray violet 

 is observed. With one half per cent, of alum the spot is a 

 reddish yellow, surrounded with a blue-gray border, and mi- 

 nute specks of blue can be observed in the dish on examina- 

 tion with a lens. . With one fourth per cent, the blue border 

 is no longer visible, but the specks can still be detected. 

 3 A, July 20, 1872, 29. 



