STANDARDIZATION-SYAIBOLS AND ROUTINE 1. Use of symbols.—Convenience is promoted by the use of symbols. A good symbol system must be: (1) unmistakable; (2) easy to remember; (3) brief.
The usual terminology of tools and parts is very loose. The meaning in which words are used differs widely among different firms, and the same word is often used for several ideas; it is consequently neces sary to determine which one is intended. The first step in symbolizing, therefore, is to adopt definite names in accordance with both current commercial usage and dictionary definitions. As one of the chief purposes of a symbol is to correct the vagueness of common language, it is essential that each symbol be applicable to only one definite thing or idea.
2. Constructing a system of symbols.—A symbol involves two things, a sign and a position. The sign may be a letter, a figure, some borrowed charac ter, such as a Greek letter, or something manufac tured to serve the purpose. Where there are enough signs to indicate all the classes, position is unneces sary. This is the case with the chemical symbols. N stands for nitrogen, whether it is at the begin ning, as in NI-1,C1 (ammonium chloride) ; in the middle, as in NaNO3 (sodium nitrate) ; or at the end.
Where, however, there are not enough signs to go around,, position is added for significance. The digit 6 means sixty in the second place (60) , and six hun dred in the third (600) . Where letter symbols are united to form groups, it is preferable to have com binations of capital and small letters, as in the chem ical symbols, rather than to have all capitals, because by the former method spaces are more easily distin guished. Each succeeding capital represents a place. In using numbers, it must be remembered that the range of any one column is 0 to 9, not 1 to 10. Where letters and numerals are used together it is better to alternate them. It is also advisable to omit the letters I and 0 lest they be mistaken for one and zero.
3. Symbols an arbitrary measure.—Symbol sys tems are "standards of measure" and must not be con tinually changed. In order to avoid confusion they must be definitely, even if arbitrarily, established. In fact many of the speakers before the American Society of Civil Engineers have claimed that this is the great advantage of a number system, since such a system makes no attempt at being logical. When it is once established there is, little temptation to alter it.
4. Advantages of mnemonic system.—Mnemonic means "aiding or designed to aid the memory." The advantage of using mnemonic symbols is that less referring to charts is necessary and consequently there is less likelihood of mistake. As a general rule, letters, especially when related to the words they stand for, are more easily remembered than numerals. The two-letter system is the one most generally used. Its 676 possible symbols are ample for most require ments. The letters should be either: first and last letters as Rm, for Ram; or first and second letters as Fr for Frame; or first letter and a letter indicating the sound as Dy for Die. Where none of these com binations is possible the same end can be attained by making the letter so extremely inappropriate as to be conspicuous. This is doubtless the idea back of the X for Inkstand in the Derby Desk system de scribed below. The memorizing of symbol systems is not so formidable a task as it appears, because each man uses comparatively few of the total number and need remember only those he uses.
5. A working one example of a well constructed system, among many that might be given, take that used by the Derby Desk Company. In this system the following capital letters, the mne monic value of which should be noted, are used to in dicate types of products: H—High roll-top desk.
L—Low roll-top desk.
C—Special roll-top desk.
S—Flat-top desk.
D—Double flat-top desk.
K—School-teacher's flat-top desk.
F—Flat-top typewriter desk.