Lime-Sulfur 51 



water. Bring the ingredients together in 

 the markt dish, place the dish on a piece of 

 asbestos over a flame, and keep the mixture 

 boiUng gently. 



Dm-ing the boiUng replace the water if it 

 gets near the 200 cc. mark. It is not neces- 

 sary that any particular volum should re- 

 main at the end of the boiling period; the 

 less water the stronger the solution and the 

 more thiosulfate is decomposed and the more 

 CaSs is formd in place of CaS4; however, if 

 the solution is made too concentrated there 

 will not be sufficient liquid to float the 

 hydrometer spindle. To make a solution of 

 the same density as the commercial prepara- 

 tions, 34° Be., it would be necessary to con- 

 centrate the liquid to less than 200 cc. 



When the liquid acquires a dark amber 

 color and the suspended sulfur has dis- 

 appeard the lime-sulfur is made. This may 

 require an hour. If the preparation is to 

 stand until the next exercise it should be 

 coverd to keep out as much oxygen a^ pos- 

 sible. Reducing the surface by placing the 

 mixture in a narrow vessel also reduces the 

 oxygen absorption. If it is intended to com- 

 plete the work at once the mixture may be 

 coold by immersing the container in water. 

 After standing observe that a crust has 

 formd on the surface of the hquid which is 



