hillebranp.] WATEK — TOTAL OR COMBINED. 41 
and by forcing a slow current of dry air through the apparatus the carbon dioxide 
resulting from the decomposition can be removed and the water carried over into 
the weighed absorption tube. The glass fuses between the platinum casings, and 
in a number of experiments that have been tried there has not been a single instance 
where the glass tube has broken or shown any indication of breaking. After beat- 
ing the tube will not crack if it is left to cool slowly on the charcoal, but it cannot 
be used a second time. * * * At the high temperature to which the glass is sub- 
ject ed it of course becomes very soft and the ends must be properly supported; also 
the rubber connections and absorption apparatus must be carefully screened by 
asbestos board. By constructing a cover for the boat no material need be lost by 
spattering, and after making the water determination the contents may be used for 
the remainder of the analysis. 
The inner cylinder of platinum serves to prevent the glass from 
collapsing as it softens, whereby distortion of the boat would result 
and its withdrawal for further examination of its contents would be 
impossible. 
GoocKs apparatus. — Of more elaborate apparatus, designed to be 
used with fluxes, the tubulated platinum crucible invented by Dr. 
Gooch 1 is capable of affording most excellent service, and it is the 
one by which far the larger number of water determinations in this 
laboratory have been made. 
Fig. 7, which hardly needs detailed description, shows it in a modi- 
fied form, which differs from the original forms of Gooch in that the 
tubes for connecting with both the drying and absorption vessels are 
constructed wholly of platinum instead of lead glass, the vertical one 
being bent horizontally at right angles for convenient attachment to 
the drying towers, and the side one also bent at right angles, but 
downward, and having its end slightly drawn in at E (fig. 7) so as to 
admit of easy insertion in the rubber stopper of a U-shaped calcium- 
chloride tube as shown in fig. 9 (p. 44). With tubes of the lengths 
shown in the figure there is absolutely no danger of their ends becom- 
ing hot enough by conduction to scorch or soften the rubber stopper 
or other connection. 
The extra first cost of the platinum extension to these tubes over 
the lead-glass ends of Gooch's original and modified forms need hardly 
enter as a factor into the question of employment of this apparatus. 
The glass ends often break, and only a rich lead glass, not easily 
obtainable, can be used, since it alone will not crack at the joint with 
the platinum after cooling. In its present form the whole apparatus 
weighs approximately 88 grams. 
As an adjunct to its convenient use there is needed an ordinary 
upright iron ring-stand, with two small sliding rings, and a sliding 
ring-burner provided with entering ducts for gas and air blast. Across 
the uppermost ring there is an arrangement of stout platinum wire 
(S, fig. 8), forming at the center of the ring a secure seat for the 
1 Am. Chem. Jour., Vol. II, p. 247, 1880; Chemical News, Vol. XLII, p. 326, 1880. 
