'290
JOURNAL OP CHEMICAL EDUCATION
OCTOBER, 1927
LABELS
The author prints out that proper labeling i s not only essential to neatness and order in the laboratory and contributory to eficient work, but has educational value as well. He discusses methods of labeling which have proved satisfactory i n his own laboratory. By their labels shall they be known. The other day I visited the chemical laboratories of a sister institution. In talking with other people who have visited these laboratories I find that I received the same unfavorable impression that they did. It may be that a high grade of work is done there, but we doubt it. What did I see? I found laboratories withno definite location for reagent bottles, and no apparent system in labeling them. All sizes and shapes of labels were used on almost any part of all kinds of bottles. Many labels were scribbled with pencil. Even in the general chemistry laboratory, the bottles were labeled with names or formulas, never both. Many names and formulas could scarcely be deciphered by an experienced chemist. No labels were protected against the action of fumes, acids, alkalies, etc. Observation showed that the condition of the rest of the laboratory was similar to that of the labels. We wonder how many laboratories would be willing to be known by their labels. We would probably pass by a store with poorly executed display and price cards. It might have high-grade merchandise, but it probably would not. The main purpose of a label on a bottle is to tell what the content of the bottle is, accurately and quickly. It may also have a positive educational value. A good label should be printed in large, legible letters and figures. Neatness demands uniformity. Uniformity requires that the same size label should be placed on similar bottles in the same relative position. This means that bottles of the same shape and size should be used as far as possible. By using bottles of the same size, shelves may be made of the proper size to accommodate them. One bottle which is too large is sufficient to upset a system. Bottles should be arranged in a definite order (alphabetically, for example) to enable the student to know where to look for a desired reagent. In order to insure that this order is maiutained, the bottles and the spaces which they occupy should be numbered. Correct labels are essential to neatness and orderliness in a laboratory. The student learns many of his formulas from the labels on the bottles, and makes many a mistake because of a bottle incorrectly labeled. A correct label in an elementary chemistry laboratory should contain the
VOL. 4, NO. 10
LABELS
1291
name and formula of the contents. In case the given substance has more than one name, the name used most widely in chemical literature should be in large type, all other names being given in small type or in parenthesis. All common names should be given for educational reasons. The formula should be complete and should conform to modern usage. For example, CuS04.5H20 should not be written CUSOI. Wherever the concentration of a reagent is required, this should be indicated on the label. In case some chemicals used are C.P. and others are not, all labels should indicate whether the reagent is c.P., commercially pure, technically pure, etc. There is a multiplicity of terms used to express the purity of reagents. We would like to have a committee appointed by the Senate of Chemical Education to standardize such terms. In a few cases labels should contain additional information showing something about the method of preparation of the given reagent. For example, one qualitative text calls for the use of a solution of As203in HC1 as a test solution. If the bottle is simply labelled AsCI3 solution, half of the students will ask the instructor if it is the correct solution to use. Another example: in the Marsh test for arsenic where arsenicfree zinc must be used, the label on the bottle containing the zinc for this test should indicate that the zinc is arsenic-free. In order to insure the permanency of a label, i t should be coated, immediately after application, with melted paraffin, white shellac, colorless varnish, pyroxylin, or some such protective coating. In case there are two sets of reagents, such as test solutions and reagents, which i t is desired to keep apart, the protective coatings may be tinted with diierent colors. This is used in addition to the numbering system. We have found that Dennison's books of numbers are excellent for use in numbering the bottles and the spaces on the shelves. We have used the books of printed labels obtainable from the laboratory supply houses, because of the following advantages which they offer. 1. The characters are more legible than those which the majority of people would use. 2. The labels are uniform in shape, and the names and formulas are placed in the same relative position on each label. 3. The use of these labels is economical. These books of labels are the same, no matter what the source, and present the following disadvantages: 1. There are no labels for many common substances. 2. There should be several labels for each of a number of the most common substances.
3. Some labels for substances such as sulfindigotic acid might well be omitted. 4. Many of the formulas do not conform to modern usage. 5 . Such abbreviations as "sodium permangan." and "sodium carbon." are confusing to a beginner. 6. Provision should be made for indicating whether a reagent is C.P. or not, and whether it is a solution or not. 7. Common names are not given on the labels.
No company or individual is interested in developing a satisfactory book of labels, because i t cannot be patented or copyrighted successfully. We would like to have this committee, which we suggested to be appointed, study this question of labels. It is almost certain that the supply companies would publish a book of labels worked out by a committee appointed by the Senate of Chemical Education. A good book of labels would be of definite educational value, and would help to solve the label problem in a chemical laboratory. We might add that we have found that the process of removing labels is speeded up greatly by using a copper sponge ("chore-boy") such as is sold for domestic use. This is particularly valuable for removing labels which have been covered with one of the protective coatings mentioned above.
