MISCELLANEOUS. 531 
decanted or drawn off with a syphon; otherwise the minute forms of Diatoma- 
cez will be lost, and the operator greatly disappointed in the result of his labour. 
Having now cleared the soundings from all extraneous matter, the next operation 
is to ascertain, by the microscope, the nature of the objects thus obtained. Take 
up with a glass tube some of the sediments, draw the contents of the tube along 
a slip of glass, and examine it with a low power. If Foraminifere or large 
Diatomacez are present, they may be removed by means of a split hair ora 
bristle from a shaving-brush, gummed or fixed in a cleft in a split of wood, and 
then placed on a clean slip of glass for further examination. If you have a con- 
siderable quantity of mud or sand under the operation, with an abundance of 
Foraminiferz, as is frequently the case, they can be separated by first drying the 
soundings, and scattering them on the surface of water in a basin; the heavy 
particles of sand will sink, but the light Foraminifere will float for a time, and 
can be easily collected. Another mode is to stir up the sediment, and then pour 
off the lighter articles into test-tubes or wine glasses. In this manner, by having 
a number of glasses, you can separate the varieties according to their specific 
gravities. If the Diatomacee obtained are recent and abundant, they should be 
separated from the calcareous portions of the soundings, and boiled in hydro- 
chloric acid ; and if not sufficiently cleaned, they may be boiled in nitric acid. 
The contents of the diatoms can be removed by burning them. Place them 
between two thin pieces of talc, and submit them to the flame of a spirit-lamp, 
Some use thin glass to support them when cleaning aquantity. Ihave burnt them 
in a smaJl platinum crucible with success. It is advisable to mount specimens 
dry, and also in balsam, for careful microscopic examination. Those mounted 
dry show the markings most distinctly. There is one difficulty which the slide- 
mounter meets with on his first essay, and which I will briefly allude to, viz., 
retaining the object in its proper place on the slide whilst the thin glass is being 
pressed down on the balsam. Some operators place the thin glass on the objects, 
and allow the balsam to flow gradully between the glasses by capillary attrac- 
tion. Professor Williamson employs a little gum in the water which contains 
the Diatomacez ; this fixes them when dry, and the balsam does not remove 
them. Some objects, such as Foraminiferz, require a long soaking in spirits of 
turpentine to displace the air from the chambers. By using an air-pump this 
process is much facilitated. A solution ofbalsam in chloroform will doubtless be 
an improvement in mounting this class of objects. It is needless to take up the 
time of the section by entering minutely into the details of mounting all the 
various objects which may be met with in specimens of soundings. Those 
interested may consult Quekett, Carpenter, and Hogg’s works on the microscope ; 
and Smith on Diatomacee. I must now apologise for taking up so much time 
on a subject which many present may be conversant with. 
P.S.—Since the above was written, several engravings, with descriptions have 
appeared in the ‘Mechanics’ Magazine,’ December 28, 1860, of the deep-sea- 
sounding apparatus invented and used on board The Bull Dog during the sounding 
expedition in the North Atlantic Ocean, under the command of Sir F. L. M Clin- 
tock, with one of these machines. Twenty-four ounces of ooze was brought up 
from a depth of 1,913 fathoms.—Jowrnal of the Microscopical Society. 
Von. VI. 2P 
