19. I n the accompanying graph are plotted fifteen points selected from the reference [I.Am. Chem. Soc.. 55, 971 (1933)). The number of squares under the curve between loe 19.31' ( = 1.2861 and loe 251- ( = 2.400) is obtained bv di&t coudting. There a r e 8 complete large squares con-
the latter are shown by squares extending beyond the line. This procedure is justified because, on the average, the numher greater than half and the number less than half will he eanal. This error of estimated sauares is minimized bv making the squares as small as posdible. I n the figure 140 small squares are counted in thismanner. T h e total number of small squares is then 200 140 or 340. But each sauare has 1 unit for a vertical side and 0.04 unit for a horiiontal side, giving an area of 0.04 unit. Then, total area = 340 X 0.04 = 13.60. The graph was made with common logarithms but the theoretical formula calls for natural logarithms. Accordingly
+
E. 53:DD .E:io C d =~
= 2.303
Cd In T = 2.303
.(151'
.19.31'
Cd log T
X 13.60 = 31.32 entropy units
Taking the entropy a t absolute zero as zero (accordina t o the third law of ihmmodynamrrs) and adding 0.08 for-the cntropy incrcasr in heating from OD to 19.31rK., the ahiolute cntroov of calcium oralate at 231°K..is31 32 + , 0.08or 31.40 entropy units. = 2.064 X lo-* 20. (a) K = (0.937 X 4.85 X AF" = - R T l n K = -1.987 X 298.1 X 2.303 X log (2.064 X lo-') = (-1364) X (g.3148) = (-1364) X (-8.6852) = +11,850 calories.
.
AFD = 5087 - 11,850 T 298.1 = -22.7 entropy units.
(h) A S o =
+Lag T . oa CALCIUM OXALATE HEAT CAPACITY taining 200 small squares; and 11 large squares that are only partially complete. The small squares in these are counted. All small squares which are cut by the line to give an area less than half a square below the line are neglected; those giving an area greater than half are counted. In the figure
AH"
-
~~~~
- --6763 298.1
- log y = c e 2 G = 0.505 X 4 X 1.393 X lo-' = 0.02814 y = antilog (-0.02814) = antilog 1.97186 = 0 937.
BIRTH DATE OF JOSEPH PRIESTLEY A NUMBER of celebrations were held during the month of March to commemorate the bicentenarv of Joseph Priestley. There seems to have arisen some confusion as to date, and for the sake of the record it seems desirable to throw some light upon this question. We have been glad to receive from C. A. Browne, under whose auspices the important and interesting exhibition of books, manuscripts, etc., was arranged at the Library of Congress during the Washington meeting, the following information which should be conclusive: I quote the following passage from Thorpe's life of Priestley, page 1: Joseph Priestley was born a t Fieldhead, in the parish of Birstall, near Leeds, on March 13 (Old Style), 1733. The Gregorian Calendar was not adopted in Great Britain until 1751. In 1752 eleven days were left out of the Calendar. Sep-
tember 3rd being counted the 14th. The change of style probably accounts for the confusion in the various dates of Priestley's birth given by different writen. I n Chalmers' "General Biographical Dictionary" the date is given as March 18; in Allen's "American Biographical and Historical Dictionsry" and in Thomson's "History of,the Royal Society" as March 24; Corry, in his "Life of Priestley," gives March 24: Hoefer, in his "Histoire de la Chimie," gives March 30, probably following Dumas's "Philosophie de Chimie"; Cnvier, in his "Eloge," says that he was born near Bristol in 17281 I n a letter t o Wedgwood, dated March 23, 1783, Priestley says in a postscript, "This day I complete my half century."
I think Priestley himself is the best authority as to his age. His completing his half century on March 23, 1783, would indicate that he begins a second half century on March 24, 1783, and the subtraction of 50 years from this would make his birth March 24, 1733.News Ed., Ind. Eng. Chem.
CORRECTION. In the table on page 366 of the June JOURNAL [ERNESTF. BURCHARD, "Sources of Ores of the Ferroalloy Metals"] quantities of vanadium ore and concentrates are expressed in pounds rather than in metric tons as the heading erroneously indicates.
