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the excess fat is shaved off with a razor blade, leaving a plane surface exactly even with the smooth surface of the block. The capillary tube, with needle suspended in its upper end, is now centered over a hole and the needle released by mithdrawing the small piece of wire from its eye. The screw head is turned to raise or lower the microscope until the cross hair coincides Tvith the top of the needle, whence the microscope is swung slightly to the right to bring the steel scale into its field, and the point where the hair crosses it is read to the nearest 0.1 mm. This reading minus the reading obtained when the needle is resting on the block gives the penetration in millimeters. The length and weight of the needle and the distance of fall are arbitrary factors, but for the products for which it was designed to test, and for the temperature range 5" to 45" C., the following were found to be satisfactory: Yo. 1 small-eye sewing needle; length, 5.9 cm. ; weight, 0.415 gram; height dropped, 20 em. The point was deliberately blunted somewhat at the beginning to avoid any error due to subsequent blunting when the needle might be accidentally dropped onto the copper surface. Certain types of fats, instead of fremiig in the holes to a uniform, smooth texture throughout, do so only in the outer portions; the center is crystalline and less penetrable and therefore to be avoided when dropping the needle. I17ith the aid of circles cut in the surface of the block about each hole as a center, it is possible to adjust the capillary tube so that the needle, when released, falls into the fat about 1 mm.
Yol. 2 . s o . 4
from the edge of the hole. About ten determinations can thus be made in one hole, or two or three a t each teniperature a t which measurements are taken; so that a complete temperature-penetration curve may be obtained for a sample placed in two holes. In the instrument as it stands there are four pairs of holes. When the measurements are completed at the lowest temperature, the water is heated to the ne-it higher by means of an immersion heater. The thermoregulator is set for this new temperature, and later more penetration readings are taken. The length of time to wait between readings a t different temperatures depends on the size of the temperature interval and upon the character of the fat. K i t h careful manipulation duplicate readings check to 0.2 mm. or better, and the temperature-penetration curves are reproducible. Results Figure 2 shows some of the results obtained. The extremes of penetrability range from aero for coconut oil a t low temperatures to 28.0 mm. for most any fat just below its melting point. The idea of using gravity as the force acting on the needle was suggested by the "G. H. Consistency TesterJJJ2manufactured by the Braun Corporation of Los hngeles. This feature, however, is the only one which the two instrument> share in common. 2
Gcddard and Hewes, U S Patent 1,703,270, F e b r u a r y ? S 19.3
Improved Bartell-Osterhof Cell' C. C. DeWitt MICKIG.4N COLLEGE OF M I N I N G A N D
TECHNOLOGY, HOUGHTON, A~ICH.
A new type of Bartell-Osterhof cell is described which Description of Cell eliminates to a large degree some of t h e mechanical Osterhof cell for measdefects of t h e original cell. uring the relative wetI n the new cell (Figure 1) T h e d a t a obtained from t h e use of t h e new cell and the outside yoke mechanism tability of solid materials was from the original cell are concordant. for holding the plunger in devised with a view to elimiThe new cell offers an opportunity t o study t h e propposition is eliminated. The nating some of the undesiraerties of liquid-liquid interfaces in contact with solids cell contains but one plunger. ble mechanical features of the without the necessity of first packing wetted material This plunger is secured in pooriginal cell (.I ). . These are: sition, while the powdered (1) The need for a special in the material is under pressure in jig for mounting the original cell in the press while compressing the material forming the the hydraulic press, by means of a few turns of a single nut. membrane. The elimination of the plunger at the manometer end of the (2) The necessity of tightening at least four yoke nuts in a cylinder does away with some of the major joint-packing very short period of time while the packed powder is under troubles. compression in the hydraulic press. Attention is called to the construction of the cylinder A . (3) The necessity for forcing or sucking the contacting liquid into the cell diaphragm of packed material. It is open at both ends and allows free passage of the liquid (4) The necessity of careful supervision of the several joints or gas through the compacted material. At the manometer at the manometer end of the original cell. end of the cell there is no plunger, and there is but one joint, (5) The lack of compactness and the unwieldiness of the cell small in area and easily tightened by means of screwing as a whole. the nut B up against a small gasket. I n spite of these difficulties, which are purely mechanical The cylinder A is made of hexagonal brass and is drilled, and involve matters of individual technic, the original reamed, and threaded as shown in the diagram. The bottom cell has yielded good results in this laboratory, where the reaming of the cylinder to a depth of 4 inches (10 cm.) is contact angles and relative wettability of various liquids perhaps the most difficult operation in the construction of with insoluble copper and iron compounds are being deter- the apparatus. The screen S rests on a small projection mined. The new cell design is submitted because it elimi- faced off by the reaming operation and fits the cylinder very nates to a large degree these mechanical difficulties and snugly; it is placed in position by being forced down through facilitates the handling of the apparatus, permitting reliable the open end of the cylinder. results to be obtained in a shorter period of time. The plunger E differs materially from that of the original cell. With the exception of the collar, the outside is uniform 1 Received June 26, 1930.
HIS improved Bartell-
T I
October 15, 1930
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and free from obstructions. The centrally bored hole is able plunger mill give the same degree of compactionlarge enough to take a 1/8-inch (3.2-mm.) diameter copper i. e., the same void space-as is obtained when a plunger tube and to allow an annular space through which the con- is provided for each end of the cylinder. I n this connection tacting liquid may flow back into the usual capillary ob- it should be pointed out that in the original technic one of servation tube. The necessity for outside yokes for securing the plungers is fixed in position as rigidly as possible before the plunger in position is eliminated by two nuts, D and C. the material is packed in through the other end. I n the Kut D performs two functions: first, it provides a means process of packing this plunger inevitably moves a little of effectively tightening the joint between the plunger and if the proper precautions are not taken. I n order to discover the cylinder wall; second, it secures the plunger in position any difference in the results obtained by the use of the original when the cylinder containing the packed material is in the cell and of the modified form described above, the mean press under a given pressure. The latter operation is, of -effective radius of the pores of copper oxide diaphragms was determined by the adaption of Poiseuille’s method worked out by Bartel! and Osterhof (2). Three types of cells were used: first, the original type; second, a modification of the type described above, which differs from it only in that it has a movable plunger a t each end secured in the same manner as in the new cell with the single plunger; third, the single-plunger type cell alreadv described. I n these determinations, 45 grams of minus 325-mesh copper F i g u r e 1-Improved B a r t e l l - O s t e r h o f Cell oxide were packed in 9-gram portions at a course, performed by screwing nut C into the female thread pressure of 2500 pounds per square inch for a period of 6 minin nut D so that the collar on the plunger is engaged. utes, the time being measured with a stopwatch. Four deterI n the process of packing the material in the cylinder minations of the mean effective radius were made with each cell, the nut B and the liquid input assembly G, F , T , etc., are benzene being used as the contacting liquid. The determinaremoved from the cell. The cell is set in the press vertically tions were carried out in a constant-temperature room of apon end, so that the pressure is applied directly to the end of proximately 800 cubic feet capacity provided with automatic the plunger E and the base of the cell. When the packing thermostatic regulation capable of controlling the temperaoperation is completed and while the contents of the cylinder ture to within *0.05’ a t 25’ C. are under compression, the plunger is secured in position ORIGINAL CELL WITH SINGLE-PLUNGER by tightening the packing nut D and then screwing down ORIGINAL CELL MOVABLE PLUNGERS CELL the nut C until it engages the collar on the plunger and the Cm. x 10Cm. X 10-6 Cm. X 10-8 1 5.47 5.51 5.52 needle of the press gage just quivers. At this point the 5.49 2 5.50 5.46 pressure is released and the cell is taken out of the press. 5.47 3 5.52 5.4s 5 51 4 5.48 5.45 The nut B and the liquid input assembly may now be screwed 5.49 Av. 5.49 5.48 into their respective places. By means of the liquid input assembly the liquid is brought The general concordance of the data shows that both into contact with the packed material under examination. modifications of the original cell give results comparable The path of the liquid is indicated by the arrows. I t will in quality with those of the original cell itself. Besides be noted that the liquid flows down through tube T, which its evident manipulative advantages, the new cell offers is almost in actual contact with the screen 8’. This tube is the possibility of direct substitution of contacting liquids closed a t one end, being soldered to a blind end bushing, for liquids actually in contact with the powdered, comwhich is in turn fastened inside the nut G. The bushing pressed material in the cylinder; that is, the original conhas longitudinal channels cut in its peripheral surface which tacting liquid may be swept out of the apparatus and an allow the liquid to flow back into the capillary observation interface established between two immiscible liquids and tube soldered into the recess in the end of the nut G. A the solid. small separatory funnel (not shown), whose stem is cut off Acknowledgment an inch (2.5 em.) below the stopcock, is soldered into the recessed, centrally-bored nut, F . By screwing F into place Thanks are due Professor Bartell for his interest in the against a small packing gasket, contact between the liquid development of the new cell. and the solid material may be readily obtained if one allows the liquid to flush the air out of the annular space inside the Literature Cited plunger. This operation forces the liquid into the capillary and Osterhof, Colloid Symposium Monoaraph, Vol. I V , p. 631, observation tube. At this point the separatory funnel (1) Bartell Chemical Catalog, 1926. with its nut F may be removed and a solid plug screwed into (2) Bartell and Osterhot, J . Phys. Chem., 32, 1553 (1928). the hole against a blank washer; or if the stopcock plug of (3) McKelvey and Taylor, J . A m . Chem. Soc., 42, 1364 (1920). the separatory funnel is well seated it may simply be turned (4) Taylor, J. Oplical SOC.4m., 18, 138 (1929). Off.
The metal-to-glass joints a t each end of the cell are made by soldering according to the method proposed by McKelvey and Taylor (S), and more recently by Taylor ( 6 ) . Comparison of Results by Original and Modified Cells
It may well be asked whether compressing the powdered material against a stationary end by means of a single mov-
Alcohol Developments in Finland-It is reported that the Finnish Government proposes to install new equipment a t the Tainonkoski plant for the production of alcohol under the Merck process, which uses lime under pressure for distillation. Although several Finnish plants have the necessary equipment, heretofore only the Mantta plant has had permission to manufacture alcohol. Deliveries by the government alcohol monopoly total approximately 350,000 liters a year.
