MOUNTING AND PREPARATION OF OBJECTS. CI 



envelope must be removed by boiling in nitric acid, 

 the sediment well washed till all trace of acid has 

 disappeared, and the residue mounted dry. 



When contained in other deposits two ounces of 

 the mixture are placed in two gallons of water, after 

 violent shaking allowed to stand two hours, and the 

 supernatant fluid removed. This process is repeated 

 till the water is no longer coloured. As much fluid 

 as possible being removed, the deposit is treated 

 with strong hydrochloric acid, and allowed to stand 

 for an hour. The acid is then poured off and a fresh 

 supply added, the whole being boiled for one hour 

 and washed in the manner first described, till all 

 traces of acid are removed. The process is repeated 

 with strong nitric acid, and after subsequent washing 

 to free it from acid, the deposit is placed in a tum- 

 bler full of water. Now comes the most trying part 

 of the preparation. 



The tumbler is allowed to stand five minutes, at 

 the end of that time its liquid contents are trans- 

 ferred to another tumbler which we shall call number 

 2, number 1 being filled and shaken or stirred with 

 a wooden rod, after standing five minutes its fluid 

 contents are tranferred to a number 3, number 1 is 

 again filled and stirred, left to stand for five minutes, 

 at the end of which time the liquid in number 2 is 

 transferred to a number 4, and the contents of num- 

 ber 1 put in its place ; number 1 being again filled 

 and left standing five minutes, the contents of num- 

 ber 3 are transferred to a number 5 and the fluid of 

 number 1 put in its place ; numbers 4 and 5 are 

 allowed to stand a quarter of an hour, the changes 



