379 



After removing from the soda, wash through a period of twelve 

 or eighteen hours in half a dozen waters, the third of which may 

 be acidulated with about ten drops of nitric acid to the ounce, 

 which acid must be washed out. Next put in alcohol, in which 

 sections and also leaves may be kept indefinitely, ready for dyeing. 



Magenta, when used for leaves, should be of the strength of 

 one-eighth or one-quarter of a grain to the ounce of alcohol, and 

 purples and iodine-green two or three times as strong. These 

 anilines are inferior to the blue in bringing out all the anatomical 

 parts of a leaf, including the beautiful crystals so often met with. 

 On removal from the dye, leaves should be thoroughly brushed 

 with camel-hair pencils. 



One week, instead of forty-eight hours, is frequently required 

 to effect the decoloration of large leaves in chlorinated soda, even 

 when they are cut into several pieces, which is advisable. 



Mr: L. R. Peet, of this city, whose stainings in aniline are un- 

 surpassed for beauty, thinks better results are attained by com- 

 mencing with a weak dye, say from one-twentieth to one-twelfth 

 of a grain, and slowly increasing the strength of the dye, at in- 

 tervals of from one to three hours, until the required hue is ob- 

 tained. This process certainly guards against too deep staining, 

 and may give a finer tone to leaves under the glass. — Geo. D. 

 Beattt, M.D., Baltimore, in Science-Gossip. 



American Association for the Advancement of Science.— 

 The 24th meeting of the Association will be held in Detroit, Mich., 

 beginning on Wednesday, August 11, next. The circular of the 

 Permanent Secretary states that the headquarters of the Associa- 

 tion will be at the Russell House, on Monday and Tuesday preced- 

 ing the meeting, and on Wednesday and the following days at the 

 City Hall and Court House, where the general and sectional sessions 

 will be held, and where the Association will be.well accommodated. 

 The citizens of Detroit have formed a large working local com- 

 mittee, comprising nearly two hundred of the leading citizens, with 

 the Governor of the State as Chairman, and we are assured that 

 everything possible will be done to make the meeting a successful 

 °ne so far as the local arrangements are concerned, while the 

 extraordinary interest taken in the last meeting by the members 

 indicates that the scientific element of the next meeting will be 



