APPENDIX 



423 



5. Formula for lime water : 



Add calcium hydrate to water till saturation is reached ; then filter. 



6. Formula for normal salt solution : 



0.6-0.75%. This solution is merely sodium chloride in distilled water. 



7. Fehling's solution for sugar tests : 



A quantity sufficient for convenient use can be made up as follows : 

 Solution 1 : dissolve 17 grams (about 1 teaspoonfuls) of pure copper sulfate 

 in 100 cc. (a quarter pint) of water. Solution 2 : dissolve 75 grams (about 

 6 teaspoonfuls) of Rochelle salt and 25 grams (about 1 5-inch sticks) 

 caustic soda in 250 cc. (about % pint) of water. Mix the two solutions 

 thoroughly. This solution keeps in usable shape only for short time and it 

 is more convenient to procure 

 tablets ready for dissolving 

 from a druggist. Whether the 

 solution is correct or not can 

 be ascertained by boiling a 

 little ; if it loses its color, the 

 solution is useless. 



8. The following is a con- 

 venient method of making 

 oxygen gas : 



Put some spdium peroxid 

 powder into a medium sized 

 flask. This should be fitted 

 with a rubber cork, through 



Illustrating the method of making oxygen gas. 



which runs a glass tube for leading off the gas, and a separatory funnel 

 by means of which water can be slowly dropped on to the peroxid at will. 

 The gas forms immediately and in large quantity. It can be most easily 



collected in jars over water by 



r\ ) downward displacement; see 



figure. 



9. To make carbon dioxid 

 gas: 



Put into a medium sized flask 

 some broken bits of marble. 

 Cover with water. Through the 

 rubber cork in the neck pass a 

 glass tube through which to 



Illustrating the method of making carbon dioxid lead off the 8 as J als a thistle 



gag, tube, letting the lower end of the 



