2 34
T H E JOUR-V.IL OF I.‘\-DLSTRIAL
irregular liming ; I 5 per cent. of the time will be consumed in filling, emptying and cleaning. Continuous settling is effected in the Deming process and in the Hatton defecators. The slightly opalescent, straw-colored juice is generally run, without filtration, merely decantation continuous or interrupted, directly t o the multiple effect. I t should be passed through fiber or gravity filters if for nothing more than to catch much cachaza that slips into the process intermittently. The decanted cachaza is washed by decantation in small tanks and then sent to frame presses for compression and sometimes washing. Evaporation is carried to 5 5 O Brix in a cane house, t o facilitate ( I ) settling and ( 2 j avoidance of false grain. The boiling of the meladura to grained massecuite is similar in principle to that carried out in a beet factory. Cane products grain with great facility, while beet products sometimes present great difficulty, conditions brought about by the variance in the character of the non-sugars, purity remaining the same. Generally three grades of grained massecuites are boiled where crystallizers have been installed, all upon a nucleus of original meladura which ranges in purity from 80-92, according to district and time of season. First massecuite, purity 80-84, yielding a sugar polarizing 97-98 O Ventzke and a corresponding green syrup or molasses of purity 60-64. Second massecuite, purity 70-74 ; corresponding molasses, centrifugated hot, 48-54 ; centrifugated after limited cooling in motion, purity 40-46; resulting sugar, washed by water or liquors t o 96’ V. Third massecuite, purity 58-63 ; corresponding molasses (final product), purity 30-3 5 ; resulting sugar polarization depending upon treatment. This last massecuite, when a t 3 5-40 O C. and 4-j days old in crystallizers, is generally centrifugated and the untreated sugar discharged into a mixer where high-grade molasses is incorporated with it and it is again centrifugated and washed to the degree desired, generally 96. This process is styled “mingling.” In factories not provided with crystallizers (which keep the grain in motion) the exhaustion of the product when it reaches the purity 48-54 must be accomplished “ a t rest,” which is brought about by discharging the final boiling, boiled “blanc” to a Brix of from 88-91, according t o conditions, into small iron wagons or into large tanks where i t is allowed t o cool quietly and crystallize spontaneously for from 12-2 I days or longer. ( T o be concluded in the -4pril issue.) -~ ~
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A MODIFICATION OF THE PARR TOTAL CARBON APPA-
RATUS E. MILLAR Received December 13, 1912 By C.
The following modification, while used by the writer in connection with the Parr total carbon apparatus, is equally applicable to any gas burette. It has not only been found valuable as a time saver
A-YD ESGI.VEERI.\-G
CHEMISTRY
Mar., 1913
but a great convenience since rapid changes of temperature and pressure are compensated for by the apparatus. When the amount of gas is sufficient to fill the pipette several times, as often happens in the determination of total carbon in soils, variation of temperature and pressure during the determination cause no trouble. I n addition the long and tedious calculations necessary under former conditions in determining total carbon in soils and coals are reduced to multiplication of the pipette reading by a constant. The diagram shows the modified portion of the Parr apparatus. When the sealed tube A is put in place and connected to B by means of D the heights of the
i;‘ I
mercury columns in the arms of D are carefully marked. The barometric reading and the temperature of the bath C, which should be a t room temperature, are also taken. It is obvious that B and G should be empty during the operation or else the core of one of the cocks E or F should be removed in order t h a t the gas in A be under atmospheric pressure. The sealed tube A is filled t o a depth of three or four inches with a portion of the same solution used in the pipette B. Since the two tubes are in the same bath the vapor pressure is the same when the height of mercury in the arms of D is the same. When a volume of gas is collected in B it is allowed t o stand until of the same temperature as C and hence of A. The stopcocks +Eand F are now opened so as to connect B and A. The leveling bulb G is adjusted until the level of the mercury in D is the same as when the apparatus was set up, in other words a t the mark.
The volume of gas is now read and after absorption in the bulb K and drawing back into B, the process of leveling and reading is repeated in the same manner. These readings give the volume of the gas absorbed a t the same molecular concentration as the gas in A when the apparatus was set up. The reading, therefore, need only be multiplied b y the factor found t o apply under those conditions. I n the bottom of the bath C there is a Bunsen valve which, by turning on the filter pump a t the top, allows a current of air t o pass through the bath C thus keeping the liquid well stirred. The tube D should be of small bore and of sufficient length t o allow for the variations of temperature from season t o season. The above modification may be fitted t o the ordinary Parr apparatus or gas pipette by inserting the stopcock E. The writer .wishes to thank Professor George H. Failyer for a suggestion that led t o the above modification. CHEMICALLABORATORYKANSASEXPERIMENT STATION KANSAS STATEAGRICULTURALCOLLEGE MANHATTAN
IMPROVED APPARATUS FOR TESTING THE JELLYSTRENGTH OF GLUES By l3. C. HULBERT
bulb, to force the liquid in the bulb-tube down t o the lower graduation 12, the cock turned to a n intermediate position and the gage read. The principal advantages of this apparatus over others are: The figure obtained is not influenced by the condition of the surface of the sample, such as formation of a tough “skin,” rapid change of temperature during the test, etc. The error due t o supporting a column of water resting directly upon the glue surface, as in another somewhat similar apparatus, is avoided; this is of especial importance in case of glues of low grade. The reading is quickly made and may be repeated three or four times on the same sample, if desired. N o error is introduced either by the apparatus itself or its manipulation ; duplicate samples, tested under like conditions of temperature, etc., give identical readings. The apparatus is simple and inexpensive and may be constructed by anyone having moderate skill in glass working. Glues may be tested either under constant cond,itions of temperature and strength of solution, or compared with a standard glue. The gage scale may be graduated in any convenient way, as by comparison with another type of glue testing apparatus, or with standard glues.
Received November 1 , 1912
SULZBBRGER & SONS Co.
The apparatus consists of a thistle tube, the stem of which is twice bent and contains three bulbs. The two larger are about z cm. diameter and serve a s safety traps ; the smaller is accurately graduated t o contain I cc. Over the mouth of the thistle tube is stretched a diaphragm of thinrubber. The far end of this tube connects through a 4-way stopcock with a gage consisting of a mercury filled U tube having its far arm extended upward and of smaller bore, this arm containing water or other liquid above the mercury. A rubber bulb is attached to one arm of the stopcock, the remaining arm being left open to the air. The sample of gluejelly is raised by means of the adjustable stand until the liquid in the bulb tube reaches the upper graduation wz,and the stand secured in this position, the stopcock meanwhile being set to connect arms A,B,C (see diagram). The cock is now turned to connect arms A , B , D and enough air forced into the system by means of the rubber
KANSAS CITY, Mo.
A USEFUL VALVE B y NATHAN S M I T H Received November 15, 1912
This simple “homemade” valve has proved very efficient in preventing the “suckback” which usually results in vacuating desiccators by water s u c t i o n , when the pressure is suddenly lowered. The valve may also be a d v a n t a g e o u s l y employed in the Kjeldahl nitrogen determination. A small evenly drawn tube, A (the tip of an old pipette serves the p u r p o s e ) , is fitted with a piece of r u b b e r , B, u-hich a c t s as a valve. A piece of w i r e , C, i s d r a w n through t h e center of t h e valve and bent a s shown. Another piece of glass tubing, D, is fitted over t h e valve t u b e l j y means of rubber connection, E. LABORATORY SCHIEFFELIS & Co., N E W Y O R K CITY
t To
T‘
rom Des iccator
