OF MICROSCOPIC OBJECTS. 45 



This must be boiled for "some moments," when the organic 

 matter will be entirely dissolved, and the calcareous shells left 

 free from impurity. They must now be x well washed in water, so 

 that all alkaline matter may be entirely got rid of. 



If the specimens are in mud, we must proceed in a different 

 way : Stir up the whole mass in water, and allow it to stand 

 until the heavier portion has sunk to the bottom ; the water may 

 then be poured off and examined to see if there are any objects 

 contained in it. This process must be repeated until the water 

 comes off quite clear, when (if the search is for Foraminifera only) 

 the solution of caustic potash may be used as before mentioned. 

 However the soundings, &c., are cleaned, it is necessary to assort 

 them under the microscope with the camel-hair pencil or other 

 contrivance, as it is impossible to obtain them fit for mounting 

 without undergoing this process. 



The sea soundings taken by order of Government are drawn 

 from the bottom in a kind of apparatus ingeniously made for the 

 purpose, and the sand, mud, &c., are brought up in their original 

 state. Common soundings, however, are taken by lowering a 

 heavy piece of lead coated with tallow, which consequently brings 

 up a small portion of the matter from the bottom. Mr. George 

 Mosley, the late Secretary of the Manchester Microscopic Society, 

 obtained numbers of the " scrapings" from the sounding leads. 

 To make any use of these it is, of course, necessary to free them 

 from all traces of the tallow. Mr. Dancer places the sounding in 

 a basin and pours boiling water upon it, which causes the melted 

 grease to rise to the surface. When cold, this may be removed, 

 and the water carefully decanted. The operation may be repeated 

 until no grease appears, when the water may be withdrawn and 

 liquor ammonice used, which will form a soapy solution with any 

 remaining grease. This must be treated with hot water for the 

 final washing. Care must be taken lest the finer forms be carried 

 away in decanting the washing liquid. Should it be wished to 

 make certain as to this point, each washing should be examined 

 under the microscope. In some cases the process of Mr. Dancer 

 will prove sufficient. Mr. Dale, however, gives a method of accom- 

 plishing the same result, which is much more readily completed ; 

 and as the results cannot be found fault with, I will here give it 



