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Correspondence -
NEW MOTION PICTURE FILM AVAILABLE We expect soon to have several copies of a moving picture film on high frequency furnaces. The film will show the melting and pouring of metals in charges of from one ounce to several pounds, clearly indicating the method of operation and the way in which electricity is applied in the furnace charge. The total length of the reel will be about SO0 feet and i t can he provided either in standard or in 16 mm. width. Copies will be available for use a t meetings of clubs, schools, and colleges. AJAXELECTROTHERMIC CORPORATION DUDLEY WILLCOX TRENTON, N . J.
SOME METHODS OF DETERMINING AVOGADRO'S NUMBER In the February issue of the JOURNAL OP CHEMICAL EDUCATION is published an article entitled "Some Methods of Betermining Avogadro's Number" by Arthur A. Sunier. The article seems to be one of the most readable ones on the subject that I have encountered, but the following errors in calculations have been noted. Page 300, line 22, 8 X should read C, X Page 301, line 37, 313 should read 316 Page 302, line 1, 6 X loz3should read 4.3 X loz3 Page 303, line 4, 4.5 X 10' should read 4.2 X lo7 Page 303, line (j, 3.1 X loLoshould read 3.3 X 10'". Sincerely yours, CAMILLE HOWELL VILLAMADONNACOLLEGC, KBNTUCKY COVINGTUN,
Editor's Note: The first recalculation listed has revealed a misprint. In all the other cases, however, the discrepancies are only such as would arise from the use of a small slide-rule or by otherwise "rounding off" numbers in calculating.
