38 PHILOSOPHICAL SOCIETY OF WASHINGTON. 
Mr. M. H. DoouirrLeE read a paper 
ON NEWTON’S VIS, 
and was followed by 
Mr. B: Pickman Mann, who read a paper 
ON REFERENCE INDEXING. 
[Abstract. ] 
The author described in part the systems of indexing the litera- 
ture of science which he had practised for many years, with illus- 
trative examples and an argument to show their general mie 
bility and value. 
He commented upon the extent and variety of the literature 
of science as a whole, and the impossibility of obtaining a knowl- 
edge of the literature relating to special departments of research 
without the aid of indices prepared for the purpose. He then 
dwelt upon the multitude of separate, partial indices now in ex- 
istence, upon the difficulties experienced in making use of these 
indices, and the waste of labor expended in disconnected attempts 
to obviate these difficulties. He adverted to the advantages which 
would accrue to all students through co-operative effort to obviate 
the difficulties described, and remarked upon the necessity, in case 
such co-operation were to take place, of determining upon a system 
of carrying it out. He considered the advantages which would be 
gained for temporary purposes by the combination of existing in- 
dices into one index to be the property of the co-operators and 
accessible either directly or mediately to all persons interested. He 
then passed to a consideration of systems by which indices have 
been constructed hitherto, and those which should obtain in the 
formation of such an index as was contemplated here. 
309TH MEETING. DerEcEMBER 10, 1887. 
By courtesy of the trustees of the Columbian University the 
meeting was held in the law lecture-room of the University building. 
Invitations to “yourself and friends” to attend the meeting had 
been mailed to all members of the Anthropological, Biological, and 
