INFORMATION TO CONTRIBUTORS 
The Proceedings is the official organ of the Academy for the publica- 
tion of brief accounts of important current researches of members of the 
Academy and of other American investigators, and for reports on the meet- 
ings ^nd other activities of the Academy. PubHcation in the Proceedings 
will supplement that in journals devoted to the special branches of science. 
The Proceedings will aim especially to seciure prompt publication of original 
announcements of discoveries and wide circulation of the results of American 
research among investigators in other countries and in all branches of science. 
Articles should be brief, not to exceed 2500 words or 6 printed pages, 
although under certain conditions longer articles may be published, 
Technical details of the work and long tables of data should be reserved for 
publication in special journals. But authors should be precise in making 
clear the new results and should give some record of the methods and /lata 
upon which they are based. The viewpoint should be comprehensive in giv- 
ing the relation of the p^per to previous publications of the author or of others 
and in exhibiting where practicable, the significance of the work for other 
branches of science. 
Manuscripts should be prepared with a current number of the Proceed- 
ings as a model in matters of form, and should be t3^ewritten in duplicate 
with double spacing, the author retaining one copy. Illustrations should be 
confined to text-figures of simple character, though more elaborate illustra- 
tions may be allowed in special instances to authors willing to pay for their 
preparation and insertion. Particular attention should be given to arranging 
tabular inatter in a simple and concise manner. 
References to literature, numbered consecutively, will be placed at the 
end of the article and short footnotes should be avoided. It is suggested that 
references to periodicals be furnished in some detail and in general in accord- 
ance with the standard adopted for the Subject Catalogue of the International 
Catalogue of Scientific Literature, viz., name of author, with initials following 
(ordinarily omitting title of paper), abbreviated name of Journal, with place 
of publication, series (if any), volume, year, inclusive pages. For example: 
Montgomery, T. H., J. Morpk, Boston, 22, 1911, (731-815); or, Wheeler, W. 
M., Konigshurg, Schr. physik. Ges., 55, 1914, (1-142). 
Papers by members of the Academy may be sent to Edwin Bidwell Wilson, 
Managing Editor, Mass. Institute of Technology, Cambridge, Mass. Papers 
by non-members should be submitted through some member. 
Proof will be sent to authors ciily on their request, in order to avoid de- 
lay in publication. Authors are therefore requested to make final revisions 
on the typewritten manuscripts. The editors cannot undertake to do more 
than correct obvious minor errors. 
Reprints should be ordered at the time of submission of manuscript. 
They will^e furnished to authors at cost, approximately as follows: 
Reprints of - - 2 pp. 4 pp. 6 pp. 8 pp. Covers extra 
Charge for first 100 copies $1 . 10 $1 . 45 $2 .50 $2 . 50 $2 . 50 
Charge for additional 100s .35 .60 1 . 10 1 . 10 1 . 00 
Copyright, 1917, by the National Academy of Sciences 
