IKDUSTRIAL AND ENGINEERING CHEMISTRY
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volumes are in error by as much as 0.05 cc., then the solubility figures can differ from the true values by 0.2 per cent and the density be incorrect by 0.002. This assumes, of course, that the starting materials are pure, that there are no handling losses, and that equilibrium is reached, so that only errors in measurement need be considered. This degree of accuracy is sufficient for many purposes, and consequently this method can be used conveniently in these cases. TABLEI. WATERSOLUBILITY MEASUREMENTS Water Saturated Substance Saturated with Substance with Water a t 20' C. a t 20' C . Substance % A d:O % A d:O 64.4 0.880 Secondary butyl aloohola 18.5 0.971 87.9 0.836 Methyl ethyl ketonea 26.7 0.962 98.5 0.745 0.990 Methyl tert-butyl etherc 4.8 0.995 99 3 0.771 -Methyl tert-amyl etherd 1.25 99.8 1.486 0.8 1,001 Chloroforme a Clough and Johns e i v e , t h e values 17.85, 0.9732, 64.17, 0.8797 ( 3 ) . Earlier work by Timmerans gives percentages of 20.2 and 63.8. b A ulot of Marshall's data gives methyl ethyl ketone saturated with water as 88.6 per cent ketone (IO). 0 Bennet and Philip give percentages of 5.83 and 97.46. Their sample of ether was less pure than that used here, boiling lower and having a higher density, indicating the probable presence of alcohol ( 2 ) . d Determinations by the synthetic method have given percentages of 1.15 end 99.4 ( 4 ) . 6 Gross and Saylor using an interferometer method, give values for water saturated with chlorAform of 0.77 per cent a t 30' C. and 0.84 per cent at 15' C. (6). Gibby and Hall by the synthetic method found chloroform saturated with water t o contain 99.93 per cent of ohloroform (6). ~
As examples of the results obtained using the apparatus described above, the data in Table I are presented. They
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represent water solubility measurements for several types of organic compounds ranging from a fairly soluble material such as secondary butyl alcohol to a fairly insoluble one such as chloroform. Wherever available the corresponding data obtained by other methods are given for comparison. The agreement is generally satisfactory, and where there are discrepancies these seem to be due in part to differences in t h e purity of the starting materials.
Summary The Hill method for solubility determinations has been investigated and a suitable general choice determined for the volume ratios employed. A simple and inexpensive apparatus is described for carrying out the determinations and experimental results obtained with this apparatus are given.
Literature Cited rilexejeff, Wiedemunn'sAnnulen, 28,305 (1886). Bennet and Philip, J. Chem. Soc., 1928,1930. Clough and Johns, IND. ENG.CHEM.,15,1030 (1923). Evans and Edlund, "Preparation and Properties of Ethers Containing a Tertiary Alkyl Group," presented a t the San Francisco meeting of the American Chemical Society, 1935. Gibby and Hall, J. Chem. SOC.,1931,691. Gross and Saylor, J. Am. Chem. Soc., 53, 1744 (1931). Hill, Ibid., 45,1143 (1923). Hill and Malisoff, Ibid., 48,918 (1926). Kablukov and Malisoheva, Ibid., 47,1553 (1925). Marshall, J. Chem. SOC.,1906, 1382. RECEIVEDMarch 6, 1936.
A Manipulator for Glass Blowing VINES COLLIER, JR., Georgetown University School of Medicine, Washington, D. C.
A
S IT IS extremely awkward and tiring to manipulate large and bulky pieces of glass in glass blowing, i t has been customary to employ some sort of rest for the object being worked. After some experience of this kind the author has designed and constructed the device illustrated. While the idea is not new, the design is and has been found ideally suited for handling any type of apparatus ordinarily constructed in the laboratory. This manipulator offers extreme flexibility in use, due to its wide range of adjustment. The actual working parts are mounted on a so!id brass rod, C, with a slotted hinge joint, E, which permits adjustment at any angle to the horizontal. This rod works in a hollow brass tube,
B, with a set screw, D, so that it may be adjusted for height. The hollow rod is mounted in a heavy base, A . In the author's instrument the hollow tube is 11 cm. high, but this, of course, depends upon the size of the blast lamp being used. The solid brass rod, which should fit snug1 into the hollow one, is 12.5 cm. from the bottom to the axis of d e hinge joint, which is made b y slotting the solid rod and rounding off the top surface. A 2.5-cm. piece of brass, F , 13mm. square, is worked down to fit the slot and the two pieces are then drilled and tapped to take a set screw, G . To the top of this square piece of brass another piece of brass, H , 13 mm. square and 15 cm. long, is joined by two screwfi in the center, to form a runner for the two carriages, 1. It is grooved all the way through except for about 2 em. in the center where thescrews attaching it to the upright pass through. It was neces-sary to place a screw at each end to keep it from warping. The top surface is milled down at an angle to fit into a cross groove in the bottom of each carriage. The carriages, made of two 15-em. pieces of brass 13 X 20 mm. are held on the runner by set screws, J . They are grooved all the way through except for 1.5 cm. in the center and are fastened at cach end with a screw to prevent warping. The carriages are" then milled to carry the uprights, K , which are made of 7.5-cm. pieces of brass 13 mm. square. The bottoms of the u rights are milled to fit snugly into the carriage groove where tRey are held in place by set screws, L. The tops of the uprights are slotted to carry Bakelite or fiber wheels, M , with a diameter of 2.5 or 3 cm. These wheels, which carry the glass, should be free to rotate easily. When constructed in this,manner i t is possible to carry a n y diameter of tubing., The wheels on which the tubing rests permit it to be rotated easily and a t any desired speed without tiring the hand by supporting. The carriages may be set close together to carry short pieces of glass or far apart tosupport longer and heavier pieces. The whole instrument.. may be tilted and used a t any angle desired. RECEIVED March 23, 1936.
