498 



SCIENCE 



[N. S. Vol. LIV. No. 1403 



error of .1 per cent. It should be -understood 



that this density refers to measurements at 



room temperature. The coefficient of expansion 



of NaCl is given by the Smithsonian Tables as 



.40 X 10"*. so that a variation of 10° C. in 



either direction from normal room temperature 



would make an error of less than .05 per cent. 



in the side of the cube. 



The volume of the unit cube of NaCl is 



therefore 



_ Mass _ 



F=T. •i„=log-i 23.34600 



Density " 



= 22.182 X 10-24 cc. 



and the side of the unit cube is 



d = log-i ¥.44867 



= 2.810 X 10-8 cm. 



Even if all the values entering into this result 

 were in error to the maximum amount, and all 

 in such a direction as to affect the final result 

 in the same sense, the change in the value 

 of d would be less than .1 per cent. 



For purposes of reference, the table below 

 gives the logarithms of the interplanar dis- 

 tances of a simple cube of side log-^ .44867 and 

 the actual distances to three decimal places. 

 These lines are all found in the powder diffrac- 

 tion pattern of NaCl. The additional lines of 

 the face-centered cube of CI ions ((i = 5.620) 

 are not included in the table as they are too 

 faint to measure easily on a film and are there- 

 fore useless for calibration purposes. 



Plane Log Distance Distance 



100 44867 2.810 



110 29816 1.987 



111 21011 1.622 



100 (2) 14764 1.405 



210 09919 1.257 



211 05960 1.147 



110 (2) T.99713 .993 



{l00(3) ^-97115 -^^^ 



310 L94867 .889 



311 T.92798 .847 



111 (2) T.90908 .811 



320 189170 .779 



321 1.87561 .751 



100 (4) 1.84661 .702 



{f22 ^-83345 .681 



{m(3) ^-82104 -662 



331 T.80930 .645 



210 (2) T.79816 .628 



421 T.78756 .613 



332 1.77746 .599 



211 (2) 1.75857 .574 



{ 100 (5) ^-74970 .562 



Wheeler P. Davet 



GeNEEAL ElECTEIC CkjMPANT, 



Schenectady, N. T. 



THE AMERICAN ELECTROCHEMICAL 

 SOCIETY 



SOCIAL EVENTS, LECTUEES 



It was generally conceded by all in attendance at 

 Lake Placid that a most unique meeting place ha,d 

 been selected for a Fall meeting. Through the 

 courtesy of the Lake Placid Club their recreation 

 facilities were placed at the disposal of our mem- 

 bers and afforded excellent opportunities for taking 

 part in golf, tennis, motoring and mountain hiking. 



A great deal of the success of the meeting is due 

 to Mr. W. M. Corse, who spared no effort as acting 

 chairman of the arrangements committee. 



On Thursday, September 29, at 9 A.M., the 

 fortieth General Meeting of the Society was called 

 to order by President Acheson Smith, who then in- 

 troduced Dr. Melvil Dewey, founder and president 

 of the Lake Placid Club. Dr. Dewey cordially wel- 

 comed our members and mentioned several points 

 of interest that everyone should see while at Lake 

 Placid. The reading ajid active discussion of 

 papers followed this talk and were continued in the 

 mornings of the next two days, the features of 

 which were respectively the symposiums on Non-fer- 

 rous Metallurgy and Electrodeposition. 



The boat ride, on Thursday afternoon, comprising 

 a round trip on Lake Placid, was enjoyed by each 

 of the 48 persons on board. 



A brief history of the Lake Placid Club was out- 

 lined by Dr. Dewey in a short talk preceding the 

 lecture on ' ' Chemistry and the Stars ' ' by Profes- 

 sor Harlow Shapley. With the aid of lantern slides 

 Professor Shapley presented a very interesting 

 account of the stellar universe and of the work 

 being done at the Mt. Wilson Observatory. 



Friday afternoon. A mountain hike up Mt. Mac- 

 Intyre was a thrilluig experience for all in the 

 party. The club lodge at the base of this peak was 

 reached by motor car through 10 miles of winding 

 roads. An unusual rain storm prevailed before the 

 party had reached the halfway mark, but this was 



