Birge, R.T.; Probable Values of the General Physical Constants
Rev. of Mod. Phys. 1 (1929) 1;

Motivation
Some of the most important results of physical science are embodied, directly or indirectly, in the numerical magnitudes of various universal constants, and the accurate determination of such constants has engaged the time and labor of many of the world's most eminent scientists. Some of these constants can be evaluated by various methods. Each has been investigated by various persons, at various times, and each investigation normally produces a numerical result more or less different from that
of any other investigation. Under such conditions there arises a general and continuous need for a searching examination of the most probable value of each important constant. The need is general since every physical scientist uses such constants. The need is continuous since the most probable value of to-day is not that of to-morrow, because of the never-ending progress of scientific research. These remarks appear to the writer so self-evident that the mere statement of them may be deemed superfluous.
However, in spite of these facts, an investigation of the values of general constants in current use in the literature reveals a surprising lack of consistency, both in regard to the actually adopted values and to the origin of such values. This is probably due to the fact that it is almost impossible to find a critical study of the best values, sufficiently up-to-date to be really reliable, and sufficiently detailed to explain the inconsistencies found among older tables. The situation is
much better in the case of selected groups of constants. Thus the best value of the atomic weight of each element is determined annually by certain atomic weight committees, and the need of such a list of atomic weights is obvious to every chemist. There is certainly a similar need in the case of the even more important constants such as the velocity of light, the charge of the electron, the Planck constant h, etc. In attempting to respond to this need, the writer has become only too well aware
of the intrinsic difficulties involved, but at the same time he has become increasingly convinced of the existence of the need itself. The present investigation was undertaken only at the express request of others, and the results given here should be considered more as a presentation of the situation than as a final solution of the problem. To obtain a satisfactory and thoroughly reliable judgment in such matters, there is required the unbiased cooperation of many persons situated in scientific
laboratories throughout the world. (Extracted from the introductory part of the paper.).

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Record comments
First step in metrology of the general physical constants.