spatula into a small evaporating dish, add approximately 2 g. of solid ammonium carbonate and some distilled water and heat for 10 minutes on a steam bath. The UOtS will dissolve in the solution, the other sulfides and hydroxides stay undissolved. After filtering and acidifying the filtrate, a brown precipitate after addition of KaFe(CN)e indicates the presence of U02. The precipitate may then be further identified with KOH, as indicated in the paper of Chao and Chen.
To the Editor: Professor Ehret's device for adjusting grades (J. CHEM.EDUC., 25, 690 (1948)) isno doubt useful, but the following points may be of interest to readers. Much labor may be saved by using a piece of 81/2 X 11-in. graph paper as normally sold for loose-leaf notebooks. Let the ordinates represent the new grades and the abscissae the grades t o be adjusted. The adjusting curve is two straight lines intersecting a t the point (0,N) where 0 represents the old average, and N the new one. Connect this point by straight lines to (0, 0) and (100, 100). An adjusted grade is obtained by taking the student's grade as x and the new grade as y from the curve. The mathematical principle behind this is exactly the same as for the sliding nomograph of Prof. Ehret. In addition this graph is constructed in about one minute a t the time needed. It lends itself to changing the desired average without being faced with the labor of constructing a new sliding nomograph. It is generally accurate to less than one percentage point. I have used this device when it seemed worth while for about seven years. It is interesting to note that the mathematics behind the idea applies more correctly to the median grade than to the arithmetic average. Naturally, in large classes this does not have any significant effect, as can easily be seen by computing the average after the adjustment has been made.
To the Editor: This is to suggest that we, as teachers of chemistry, do what we can to disentangle the two meanings of the word theory for the benefit of students, and perhaps also for our own benefit. The primary meaning of the word theory is an explanation of observed facts. This use of the word is in accordance with its origin and is solidly established. But in scientific work, the word theory is also used to denote the principles of a branch of knowledge; for example, the theory of equations. Since persons of brilliant accomplishment in "theory" are often less accomplished in the "practice," there is a tendency for the confusion in meanings to discredit theory in the sense of an explination. It is suggested that the abstract knowledge of an art might better be referred to as principles, reserving the word theory for explanations. Carrying this one step further, it is suggested that the calculated yield in a chemical preparation might better be called an ideal yield, not a "theoretical" yield. It has been said that there is nothing so practical as a good theory.
WILLIAMS. HORTON
AND TECHNICAL YORK
UNIVERSITY OF CONNECTICUT STOER~. CONNECTICUT
To the Editor: The following suggestion is offered as a modest conTo the Editor: tribution to the cause of national self-improvement. Sometime ago I was examining the alkaloid chapter Ting-Ping Chao and Shih-Chia Chen describe a method for the detection of Uranium in group I11 in Gilman's "Organic Chemistry." I learned from it (THISJOURNAL, 25, 686 (1948)). During my freshman that the chief ingredient of betel nut is a simple nicoand sophomore years a t the T. U. Berlin we routinely tinic acid derivative called arecoline. I learned also analyzed mixtures containing several of the following that chewing the nut induces "a feeling of well-being, elements: As, Sb, Sn, W, Mo, Hg, Ag, Bi, Cu, Cd, Pb, good humor, and contentment." Now, a sense of well-being, good humor, and conU, Al, Cr, Mn, Fe, Co, Ni, Zn, Mg, Ba, Sr, Ca, NH4, Na, K, and Li, together with anions, some of them tentment is the one commodity which this country (CzO4--, CJI@--, HPOe--) disturbing the routine of needs desperately a t the present time. In spite of their analysis. Our method of detection of uranium seems material blessings most Americans are unhappy, frusto me simpler: take the mixture of the precipitate of trated, and short-tempered. They are prey to all sorts group 111 (UO& A1(OH)3, CC(OH)~,FeS, CoS, NiS, of anxieties and phobias. The sharp exchange of angry words may be heard ZnS, MnS), remove a little bit with a clean porcelain 286
MAY, 1949
everywhere-in the halls of Congress, over the radio, and down at the corner store. Every human relation has been poisoned by malice and fear. Every face has been worn thin by the deadly competition of the market place. Occasionally, the national neurosis explodes in a strike riot or a lynching. Violence has become the safety valve of a nation which never has learned to relax or to look a t itself objectively. Here is a golden opportunity for creative chemistry to save us all. For about twenty million dollars the government could build a plant large enough to turn out arecoline by the hundreds of tons. Suppose, now, that the law made it compulsory for processors to put small quantities of arecoline in such things as coffee, cigarettes, ice cream, beer, and soft drinks. America would be made over in no time. With everyone feeling healthy, good humored, and contented the transformation in our national character would be both startling and gratifying. Suddenly, Old Guard Republicans would h d themselves speaking well of Mr. Truman, while rabid New Dealers would smile pleasantly upon wheel horses of the N.A.M. Even ordinary citizens would back away from a street collision with polite bows and promises to pay-instead of profanity and fisticuffs. Anything that would free this country from hatred, fear, frustrated ambition, and bad manners would he the most marvelous innovation of all time. The atomic bomb would be a piffling project by comparison. I earnestly commend the virtues of arecoline to government planners.
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little problems and questions to which I can trace no answer. I do not feel that any scientist should be ashamed of admitting ignorance over anything. Personally I should lose all interest in chemistry if I knew all the answers. "I don't know" is the stimulus which spurs one on to OF CHEMICAL EDUCATION 6nd out! I find the JOURNAL tremendously stimulating.
To the Editor: Since the publication in THISJOURNAL of the article on "A device for adjusting grades" (25, 690, December, 1948) there have been a number of inquiries about how to draw up a set of tables which could be used as a substitute for the grading scheme presented in the article. Perhaps the best way to show how this would be done is to give an example and then state the rules to be followed in making-up.similar tables for different conditions. The following is a table that may be used to adjust grades to a 75y0 level or "standard" average when the average of the raw scores for a class was 6601,. The ," left- a i d right-hand columns represent raw score values and the central column contains the number which is to be added to t,he raw score to adjust it to the 75% level. R G 9 4 Q
T o the Edilor: I have read with interest the letter in the February issue suggesting the term AVOGRAM be associated with an atomic weight unit. Being personally somewhat a "relativist," having a few chemical engineering friends who would dislike the word AVOPOUND, but above all being impressed by a letter signed by no less than three former teachers, I am puzzled. All I can do is suggest that the term SIXTEENTHOX might be better. I t has two advantages: one, its etymology oxygen atom) is obvious; and two, it is just silly enough that students would soon realize why no name has until now been thought necessary for this quantity.
T o the Editor: May I support Dorothy W. Gifford's remark in the January issue, page 52, that she would like to see an Information Service. As a teacher I constantly come up against puzzling
The steps in setting up similar tables are: (1) Subtract the class average from the "standard" average. If the difference is positive, corrections are to be added to the raw scores, if negative, they are subtracted. (2) Divide the class average by the differencefound in (1). The quotient represents the "steps" between the grades in the left-hand column. When, as in the case illustrated above, the quotient is not a whole number, slight adjustments must be made in the increments or "steps" to compensate for the fractional parts. (3) The difference found in (1) becomes the top number in the central column, which contains the corrections. These corrections diminish by integral steps. (4) Divide 100 minus the class average by the M e r ence found in (1). The quotient represents the steps between the grades in the right-hand column.
