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Comparison of the various corn starches: CHR. E. G. PORST AND M. MOSKOWITZ. The Bingham-Green Plastometer is adapted to the examination of various corn starch pastes, alkali, acid and thin boiling (Herschel and Bergquist, Journal of Ind. & Eng. Chem., Vol 13, 703). A short review of the derivation of the formulas required is given. Type curves and tabulated data on the various starches investigated are included. The effect of the temperature of cooking on the properties of the pastes is noted and the need of more accurate formulas suggested.
An inquiry into fundamentals of sugar colorimetry: H. H. PETERS AND F. P. PHELPS. The spectrophotometric investigation of impure sugar products is continued, and the asbestos method of colorimetric clarification and filtration, which was reported in a previous paper, is further critically examined. Beer's Law is valid for concentrated impure sugar liquors (50 Brix), but dilution with water changes the degree of dispersion and colorimetric value of the colloidal nonsugars, invalidating Beer's Law. A new method, using concentrated granulated syrup of known spectral transmissivity for the dilution of heavily colored, concentrated syrups in place of water is presented.
The testing of quartz control plates: F. P. PHELPS. Quartz control plates are used in precise sugar work to eliminate all errors due to variations in the polariscope itself. All quartz plates sent to the Bureau of Standards are subjected to the following tests: (1) Examination of the mounting. (2) Homogeneity of the quartz. (3) Planeness of the faces. (4) Parallelism of the faces. (5) "Axis Error." (6) The precise measurement of the rotation from which the sugar value is calculated. A tentative set of specifications for quartz control plates has been drawn up as an aid in the production of plates of uniformly good quality. It is very important that all quartz control plates be standardized at some central agency such as the Bureau of Standards. The maker's value, which is stamped upon the mounting, can not be relied upon, in fact, plates have been tested at this bureau whose true sugar value differed from the maker's value by approximate 0.°2 of a sugar degree.
The origin and development of the cane sugar industry in America: C. A. BROWNE. The history of plantation cane sugar manufacture in America is briefly sketched with help of lantern slides and old engravings from 1493 down to the
present day. The evolution of the mill, evaporator and other machinery is traced with descriptions of such curiosities as Stuart's steam mill and Bessemer's crusher. The methods of white sugar manufacture in Cuba by means of bone black between 1850 and 1860 are described. In conclusion the origin and development of the modern central system are discussed with particular reference to the future growth of the industry.
Enzyme method for determination of raffinose in beet sugar-house products: H. S. PAINE AND F. W. REYNOLDS. The method of Hudson and Harding, which depends on the hydrolysis of raffinose by invertase with formation of melibiose and fructose, and subsequent hydrolysis of melibiose by means of the enzyme melibiase, was adapted for the examination of beet molasses and other sugar-house products. The molasses solution is clarified with basic lead acetate and a small amount of norit, and, after suitable adjustment of the acidity, top yeast extract, containing the enzyme invertase, and bottom yeast extract, containing the enzymes invertase and melibiase, are added to equal portions of the clarified molasses. The difference in the polarizations is a measure of the amount of raffinose present. The success of the method depends upon the use of highly purified and concentrated enzyme preparations.
Rôle of fermentation in the deterioration of cane sugar products: C. A. BROWNE, C. A. GAMBLE, G. H. HARDIN AND M. H. WILEY. The average quality of the raw cane sugar manufactured in the tropics has shown but little improvement during the past five years. Only about 35 per cent. of the Cuban factories make good-keeping sugar of low moisture content. Sugars during deterioration become more hygroscopic, owing to the invert sugar that is formed, and the additional moisture absorbed from the atmosphere accelerates the activity of the destructive microorganisms. The chief requirements for making a good-keeping sugar are: (1) Cleanliness in the factory to prevent infection; (2) A moisture content sufficiently low to retard the growth of yeasts, moulds and bacteria; (3) Bagging the sugar after it has cooled to prevent sweating; (4) Storage in clean, dry warehouses in piles that are not high enough to burst the bags. The deterioration of soft refined sugars is less rapid than that of raw cane sugars of the same polarization. Sugar cane molasses also undergoes deterioration during storage with destruction of both sucrose and invert sugar.
The manufacture of chemically pure dextrose: C. E. G. PORST AND N. V. S. MUMFORD. The development of a method of manufacturing chemically pure dextrose using crystallization from water only is described. The first method used necessitated an alcohol wash and a crystallization from alcohol. This method had to be abandoned owing to excessive cost and another method developed. This method used "Cerelose" as a raw material and "Eponite" as a decolorizing agent. This method had to be abandoned to allow an increase in capacity. Boneblack is now used for decolorizing and the raw material is "Refined Cerelose' made by the Porst and Newkirk method. Difficulties encountered and methods of overcoming them are described.
The purification and concentration of enzyme solutions for the rapid analysis of sugars by enzymotic hydrolysis: F. W. REYNOLDS. Preparations of the enzymes invertase and melibiase were purified by dialysis followed by treatment with a very small proportion of acetic acid, which caused flocculation of impurities. Substances which stabilize the impurities flocculated by acetic acid are apparently removed by dialysis. treatment is fully as efficient as clarification with neutral lead acetate and does not cause loss of enzymic activity. The filtrate may then be concentrated to practically any desired extent by ultra-filtration, using collodion filters of special composition. Highly active and brilliantly clear solutions of invertase and melibiase of great stability were thus obtained. This method of purification and concentration permits the use of these enzymes as analytical reagents, for rapid analysis of sucrose and raffinose. The construction of a suitable ultra-filter from materials generally available is described.
The estimation of raffinose and sucrose in beet products: R. F. JACKSON. A modification of the enzyme method permits an accurate determination of true raffinose without the difficulty of measuring small changes in polarization in the presence of large amounts of invert sugar. After sterilization of the molasses, the greater part of the invert sugar is removed by fermentation with bakers' yeast. The solution containing the melibiose is filtered, evaporated and divided into two aliquots, which are diluted one tenth, one with water, the other with the invertase-melibiase solution extracted from brewers' yeast. After hydrolysis, both are analyzed for reducing sugar. The difference between them is a measure of raffinose. The method is not standardized against
pure raffinose. By the above method analyses were made of samples of Colorado beet molasses. True raffinose was found to be sometimes less and sometimes greater than that indicated by Clerget. From the true raffinose and true sucrose, the direct polarization of the sugars was computed. The difference between the calculated and observed direct polarizations give the rotation of the non-sugars. In every case these proved to be negatively rotating.
A simple diffusion battery for laboratory and lecture room experiments: M. J. PROFFITT. Each cell of the battery consists of a friction top tin can to the inner walls of which near the bottom is soldered a circular woven wire screen molded to a concave shape. A suitably bent copper tube is soldered with a perforation in the side of the can below the screen, and it extends on the outside above the top of the can, to connect with the juice line. It may be provided with a steam jacket for a colorisator. Two short copper tubes are soldered into perforations in the lid of the can, one for an air-vent and the other for connecting to the water-line. The juice, water and cross-over lines consist of glass T-tubes with rubber connections and pinch-cocks. A 14-cell battery without colorisators requires 14 friction top cans, enough wire screen to make the screens, depending upon the size of the cans used, about 60 pinch-cocks, 60 glass T-tubes, 20 feet of copper tubing, some solder, and 50 feet of thin-walled rubber tubing. At current prices, it will cost about $30 and require one day's time to set up. It serves for experiments on water extractions and for familiarizing students with the actual operation of the diffusion process as carried out in the manufacture of beet sugar.
Precipitation of gum from beet molasses: H. S. PAINE AND C. F. WALTON, JR. In order to permit a study of the properties of the gums present in beet molasses, and the effect of such gums on the analytical control and certain phases of the factory process, the following method of preparation was evolved. It is considered more rapid than the dialysis method previously described. Each kilogram of molasses is diluted with 10 liters of water, and to this solution are added 1.4 liters of ammoniacal lead acetate and 0.4 liter of strong ammonium hydroxide. After filtration of the precipitate, it is suspended in water and decomposed with 1:4 H2SO in carefully regulated amount. The filtrate is neutralized with solid barium hydroxide in the cold, concentrated in vacuo and dialyzed against running tap water.
This solution is clarified with neutral lead acetate, and after removing excess lead with HS the dialysis is completed against distilled water. The specific rotation of the gum obtained, on the basis of total solids in the purified solution, was - 38.08.
Chemical properties of the gum from cane affected by Cobb's gumming disease and its influence in the sugar-house: C. F. WALTON, Jr., AND O. S. KEENER. Observations were made in Porto Rico of the effect of a gum similar to that from Cobb's gumming disease on factory operations. A somewhat concentrated solution of the gum purified by filtration and dialysis was found to polarize 0.06 V. in a 2-decimeter tube. After hydrolysis with 1 per cent. hydrochloric acid this rotation changed to +0.01 V. The solution after hydrolysis reduced Fehling's solution strongly but gave no test for pentose. Total solids by the Westphal balance corresponded closely to the amount found present by drying. Although the substance was found to be optically active, it was completely precipitated by basic lead acetate as in the usual method of analysis. On the basis of these and other experiments, it is believed that the presence of this gum in cane juice does not interfere with the laboratory analyses.
The dietetic value of sugar: W. D. HORNE. The extremely high food value of sugar is not adequately realized. As a producer of heat and energy in the body it is cheaper than almost any other food. With its high calorific efficiency, quick digestibility and present low price, it should logically be used in much larger quantities in old world countries where food and money are scarce. Europe averaged 37 pounds per capita per annum before the war. The United States now averages 86, and New Zealand in 1911 averaged 130. The United States could increase her consumption 20 to 30 per cent. advantageously and Europe much more.
Organic and inorganic composition of corn: C. E. G. PORST AND MISS J. F. MOHRING.
Some new processes in the sorghum syrup industry: J. J. WILLAMAN. The sorghum syrup industry is being given a new impetus by certain developments in its process of manufacture in a Minnesota factory. The principal ones are: (1) A cleaning machine, which does away with hand labor entirely in the harvesting and cleaning of the cane. (2) Instead of the wasteful settling process of clarification, the whole juice, after defecation with heat and lime, is filtered, infu
sorial earth being an ideal filtering medium. (3) Treatment of the filtered juice with activated charcoal produces a light colored, mildly flavored product. (4) Evaporation in a vacuum. (5) The seed heads are dried and constitute a valuable by-product. (6) The leaves and bagasse are continuously fed into the fire-boxes, and constitute 85 per cent. of the fuel. (7) The cleaner has reduced the labor hour cost per gallon of syrup from 1.3 hours to 0.7 hour. (8) The cheapening of the processes, the improvement of chemical control, and the breeding of pedigreed and improved cane, have inaugurated a new era in sorghum syrup manufacture.
Note on the first uses of the polariscope in the United States for sugar testing: C. A. BROWNE. A search of available records indicates that one of Biot's early polariscopes was used in the sugar refinery of J. S. Lovering & Co. in Philadelphia as early in 1843. Two Ventzke polariscopes were imported about the same time, one by the chemical firm of Booth & Boye of Philadelphia, and one by Professor R. S. McCulloh, of Jefferson College, for his research upon sugar and hydrometers for the U. S. government. Information is lacking as to the date of the importation of the first Soleil saccharimeter. An old Soleil instrument used by Valcour Aime of Louisiana and now in the Louisiana State Museum is probably of about the date 1850.
Preparation of fructose from invert sugar: T. SWANN HARDING. Fructose was prepared by fractional crystallization from invert sugar obtained by the hydrolysis of sucrose by invertase. It was found necessary to recover by the first crystallization 36 to 371⁄2 per cent. of the weight of sucrose taken as glucose. The yield of fructose subsequently crystallized amounted to 23.5 to 28 per cent. of the weight of sucrose taken. The sirups were mixed with glacial acetic acid before setting aside to crystallize. The fructose was recrystallized from alcohol. The effect is discussed of various factors, such as acidity and temperature, on the crystallization of fructose.
Analyses of mixtures of reducing sugars and sucrose with Quisumbing's Fehling solution method. A. W. THOMAS. Analyses of known sugar mixtures containing sucrose give more nearly correct results when using the new Fehling reduction method than has been possible by any of the older reduction methods.
CHARLES L. PARSONS, Secretary
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OBSERVATION VERSUS EXPERI-
IN gatherings of scientific men such as this one, it is customary to have a number of nontechnical addresses, which often take the form of general surveys of certain fields of science, with summaries of what is known in various directions, and with indications of problems which await solution. The topic which I have chosen, however, would indicate that for the moment it seems to me worth while to stop and discuss somewhat the methods of science rather than the results. No doubt all of us look upon both observation and experimentation as necessary evils, the means to arrive at ends or results which are much more important and attractive in themselves than are the processes of obtaining them.
Before a company of astronomers the contest between observation and experimentation might be anticipated to mean a discussion of the relative merits of the old and new astronomy, the astronomy of position, or of precision as its devotees often call it, and the newer field of astrophysics. Or the contest might be between the whole field of astronomy on the one side and the domain of physics and other experimental sciences on the other, for we astronomers have the reputation of being precise and painstaking observers, while the experimenters have, to our minds at least, the habit of spending most of their energies in getting ready to be precise, and then when they are prepared to take what we would call observations, their aim is achieved and they pass on to something else. But my purpose is rather to consider somewhat the struggle which often goes on in the mind of the investigator himself, whether he shall after a certain amount of
1 Address of the retiring vice-president and chairman of Section D-Astronomy, American Association for the Advancement of Science, Toronto, December, 1921.
preparation begin observing, or whether he shall consider that his conditions are not yet favorable for exact work. Likewise the question may come up in any long series of observations: When is it better to stop and try to improve things rather than to go on in a routine? A similar choice may come to an individual even in deciding his preference for one science or another, and in the fundamental sense this same choice runs through much of our lives, the attraction of the old versus the
While we may take up certain considerations from the limited point of view of astronomers, there are undoubtedly applications of these same ideas in many fields of science. Of course we are all interested in improvements, and no one of us would care to admit that he has not the patience and concentration to keep at a task until he has mastered it and can do it well. There are, however, differences in individuals, and as time goes on these are accentuated, and each worker naturally tends to gravitate into the field where he works best and feels at home. The skillful observer is usually an orderly person who keeps his surroundings and apparatus neat and tidy. His instinct is to maintain constant conditions, and if his instrument or apparatus is working perfectly, to let everything remains undisturbed. There is good reason for this, since experience often shows that variation of conditions introduces unsuspected errors. The experimenter, on the other hand, seems to take delight in being surrounded by the débris of his work. Order and system are not part of his creed. He has no hesitancy in dissecting any fine new instrument if some of its pieces will fit in with what he wants, probably much to the consternation of his colleague who is responsible for the equipment. Whenever the observer sees or does anything, he writes down a note, but writing is the last thing of which the experimenter thinks. The observer takes apparatus as it comes to him, the experimenter improves apparatus or devises something new. The observer keeps all or almost all his work, the experimenter has no scruples in throwing away anything which he thinks he can improve upon. I remember visiting a laboratory in company
with a prominent astronomer, where we were shown some spectrum photographs. physicist in charge showed us a negative which he had just taken, and then threw it aside. My companion promptly asked if there could not be something of value on that plate, if it should not be kept. The experimenter answered that he had dozens equally poor, and that he could reproduce it at will. To the observer even a poor photograph may represent an opportunity which will never return.
It is much easier to teach large classes of students to observe, after a fashion, than to experiment. In a laboratory section, the student will consider favorably a system which enables him to come in and sit down at his table, and without delay to begin and simply take readings. We hear a great deal about teaching the scientific method, but it would be quite impracticable to inflict upon elementary students the real methods of science, the trials and waste of time which any one must undergo before he can determine what he needs, and then find and assemble his apparatus.
There is one direction in which an observer sometimes feels that he has the advantage over the experimenter, and that is in this matter of waste of time. An hour's work for the observer brings an hour's results, whereas the experimenter often puts in a great deal of effort with apparently no return. A safe program of observation brings in sure returns; but is not any one mistaken in assuming that he can avoid waste of effort? It is the fate of most scientific work to be superseded, and the most accurate observations are likely to be quite out of date even in the lifetime of an individual. Bradley's star places have been and are still of great importance as a basis for proper motions of stars, but the time will come when the so-called modern observations will be of the same order of antiquity as those of a century and a half ago, and Bradley's observations will gradually lose their importance. On the other hand, there are many results from positions and proper motions of stars determined from current measures which are obviously of permanent value. Such a case is Boss's cluster in Taurus, a group of stars now widely dispersed, but which as time goes on