hillebrakd.] USEFUL AIDS IN CHEMICAL MANIPULATION. 
23 
« 
and ferrous iron determinations. But such an output of work is more 
than exceptional and implies an unusual freedom from those occa- 
sional setbacks to which every chemist is exposed. 
It should here be remarked that the Survey laboratory is most excep- 
tionally well supplied with all kinds of platinum 
vessels and utensils, so that it is rare indeed for 
delay to arise through lack of dishes of even the 
largest sizes. 
V. TWO USEFUL AIDS IN CHEMICAL MANIPU- 
LATION. 
In connection with the foregoing remarks it is in 
place to mention two aids to the chemist which are 
in constant use in this laboratory and have come 
to be well-nigh indispensable. Neither is novel in 
principle and both are in use elsewhere, but they 
are not so commonly known as they deserve to be, 
hence this allusion to them. 
Fig. 1 represents a form of platinum-tipped cruci- 
ble tongs devised by Dr. A. A. Blair many years 
ago. With them a crucible can be securely grasped 
and brought into any desired position while still hot. 
To the contents, if in fusion over the blast flame, 
can be imparted the rotatory motion so often desir- 
able. Above all, the cover need not be in the slight- 
est degree displaced, as when using the common 
form of platinum-tipped tongs. 
Fig. 2 represents a very useful adjunct to the 
worktable and especialh T to the draught cupboard, 
whereby the liquid contents of crucibles can be 
speedily evaporated at almost any desired tempera- 
ture and the dehydration of many solids effected 
much more safely than on an iron plate or sand 
bath. I do not recall who originated this form of 
air bath, but it has been in use here for over fifteen 
years and is identical in principle with the later 
Nickel-becher of Jannasch. Nickel undoubtedly 
has a certain advantage in not rusting as does iron, 
but the form depicted in K of fig. 2 can easily be 
made anywhere of sheet iron riveted at the joint, 
the bottom (not shown in the figure) being securely 
held by a flange at the extremity of the truncated cone. A crucible 
placed on the platinum triangle becomes uniformly heated by hot air, 
and large quantities of Liquid, even sulphuric acid, can be thus vola- 
tilized in a short time without ebullition or spattering. 
Fig. 1.— Platinum-tipped 
crucible tongs. The 
parts A B, also of heavy 
platinum, are hollow, 
to serve as sockets for 
the cheaper metal of 
tlic handles. 
