Memorandum to Mr. Dimick [C.H. Dimick], September 23, 1919

copy for Dr R. L. M. C. INTERIOR MEMORANDUM 9/23/19 Date Subject Mr. Dimick. For Attention of Answering Memo. of COMPARATIVE LUMINOSITY OF 'UNDARK' AND 'LUMA. Below is a table that shows the measurement of luminosity, the net price, and the cost per unit for six samples of Luma and eleven samples of Undark:- leasurement Net Price Cost per Unit JUNE Luma 6 19 $ 18.50 $3.52 5 21 13.25 2.78 4 23 12.25 2.82 3 25.3 10.50 2.66 2 28.5 7.00 2.00 1 37. 3.50 1.20 JULY R.L.M. B 16 17.25 2.76 D 17 12.00 2.04 E 20 8.10 1.62 F 21 6.00 1.26 G 22.7 4.35 .99 H 26.5 3.25 .86 I 30 2.25 .68 J 34 1.75 .60 39 1.45 .47 L 47.5 1.25 .59 M 57 .85 .49 The measurement ie a record of the reading taken in our labor- atory and is probably as accurate 8 8 it is possible at this time to make obser- vations of luminous material. As you know, this work is all done in the dark. The operator does not know what the reading will be untilnafter his measurement is made and his gauge fixed. Thie method insures accurate and aprejudiced readings. The samples of Luma were secured in Junen and were delivered before the materials had reached their maximum or point of equilibrium 80 that these maximum readings can be considered to represent best Luma quality. Somotimes we secure samples of competitors' materiale and we are not sure of the dates of man- ufacture, whether the material is new or old or the condition in which it has been kept, etc., so that we are not always sure that we are doing our competitors full justice in making the readings, but in the case reported above, we are convinced that the comparisons are extremely close and well made. The measurements as read show a lesser amount for high lumin- osities than for low luminosities. In other words, the scale ie reversed. Thie has been corrected in Column #3 showing cost per unit of luminosity, the unit of course being an arbitrary factor but necessarily a constant in all readings. The net price for Luma is their regular quotation less 10 % which NO believe corresponds to our minimum schedule. It is safe to assume that should this not be a fact that these prices are not more than another 10 % out of the way. (Continued)