APPENDIX III. 

 APPARATUS AND REAGENTS. 



The chemicals required are so few that in most cases they 

 may be most conveniently obtained through local dealers. It is 

 desirable, however, to order apparatus from dealers who make a 

 specialty of manufacturing or supplying optical, chemical, and 

 physical apparatus. Schools are entitled to import such appara- 

 tus free of duty, and by doing so through importing firms a large 

 part of the cost may be saved. The list is given here for its 

 convenience as a summary. The amounts necessary are not 

 specified as they vary with the size of classes, and the teacher 

 who is prepared to conduct the experiments can readily deter- 

 mine how much is needed. 



CHEMICALS. 



Acttic acid. — Used for fixing protoplasm. 



Alcohol. — Large schools should buy in barrel lots free of reve- 

 nue tax. For regulations apply to the revenue collector of the 

 district in which the school is situated, or to the Secretary of the 

 Treasury. 



Ammonium hydrate (ammonia). 



Barium hydrate. — For making baryta water; or this can be ob- 

 tained fresh as needed from druggist. 



Chromic acid. — Used in fixing and decalcifying. 



Corn starch. — As prepared for table or laundry. 



Formalin. — This is a 40 per. cent solution of formaldehyde in 

 water. Dilute solutions can be prepared as needed. Most 

 plants require a 10 per cent solution, i.e., formalin i part, water 

 q parts. 



Grafting max. — Made as follows: Melt together resin (by 



409 



