614
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
shape while attached t o the buret, both being placed in hot water. The form shown in Fig. 2 can be p u t on or be taken off the buret a t any time, by simply sliding the sleeve along the buret until the tines of the fork are free from the stopcock, and then sliding it down along the tube until it is free. After I had used the Munroe clip for some time, and had become familiar with the security it affords against the accidental breakage of stopcocks, it occurred t o me that for new apparatus, a glass stopcock could be easily constructed which would be quite free from the danger of the cock slipping out. In the preparation of glass stopcocks the cock is always cut off from a longer piece of glass, and it should be a simple and easy matter t o leave the glass a little longer than is now usually done, and then after grinding the cock a small groove could be cut in this extended portion. By wrapping a rubber band around Ply 5 PLY 4 in this groove, or attaching a small rubber ring, complete security would be afforded against the accidental loss of the cock. I had some stopcocks prepared as shown in Fig. 4, fitted with a small rubber ring as indicated (partly in section) in Fig. 5 . The device affords absolute security against accidental loss of the cock, while a t the same time it is nearly invisible, is not in the way of the operator, and can be instantly removed when required. It further serves t o keep the cock in place, preventing the loss of fluid which sometimes results from a cock becoming slightly displaced. The form of holder devised by Dr. Munroe can be readily applied t o any type of glass apparatus already constructed, and the form I here suggest can be provided on new apparatus, thus offering for either new or old apparatus a remedy for the nuisance of broken stopcocks.
I
B Y GUILFORD L . SPENCER.
Received April 29, 1912.
The writer tried unsuccessfully t o use alundum crucibles in the ordinary Gooch holders, in the gravimetric determination of reducing sugars. The difficulty experienced was in washing the walls of the crucible free of the salts. I t later occurred t o me t o make the joint a t the top of the crucible instead of near the bottom, as in the Gooch method. To do this required a special funnel and a rubber ring, which I procured through Messrs. Eimer & Amend. The arrangement of the apparatus is shown in Fig. I . The results are satisfactory. The air pressure causes the rubber ring t o bear upon the edges of the crucible and against the wall of the funnel, making tight joints. The supporting points in the funnel leave all parts of the crucible accessible for washing. With the glass funnel, as illustrated, there is some slight difficulty in centering the crucible. I propose to overcome this in the 1 8 future by the use of a porcelain funnel with centering points, as shown in Fig. 2 , or a perforated diaphragm. I believe t h a t with this arrangement the alundum crucible will be very useful in gravimetric f i9.2. work in agricultural and general laboratories. I expect soon t o use it in P,O, determinations. An evident advantage of this type of crucible is the absence of asbestos.
a +.
THE CUBAN-AMERICAN SUGARCOMPANY, Y O R K AND
ADDRFSES
NATURAL GAS INVESTIGATIONS OF T H E M1NES.l
BUREAU OF
By GEORGEA. BURRELL.
Last year a t the Pittsburgh convention of the Natural Gas Association, a resolution was passed, asking that the Bureau of Mines assist the natural gas industry in solving problems which arise in the utilization and conservation of natural gas. Although not as active in its investigations as it hopes t o be in the future, some progress has been made toward a study of this important fuel. N o attempt has as yet been made toward a complete Presented at the 7th annual convention of the Natural Gas Association of America, Kansas City, Mo., May 21, 22, 23, by permission from the Director of the Bureau of Mines.
1912
ALUNDUM CRUCIBLES IN GRAVIMETRIC ANALYSIS.
NEW
BUREAUOF MINES, WASHINGTON
Aug.,
HAVANA.
1
comparative study of the natural gases from different fields of the country. Some work has been accomplished in t h a t the characteristics of the gas from a few wells in some of the more important fields have been determined, but the Bureau is gathering from many wells in all of the fields a large number of samples, and is submitting them t o examination. A bulletin covering this work will be ready for distribution the latter part of the present year. Work already accomplished makes i t appear t h a t natural gas consists of paraffin hydrocarbons with nitrogen and carbon dioxide as impurities. The ,paraffin hydrocarbons may be methane only, or a mixture in which methane and ethane predominate with smaller percentages
