Junk 23, 1899.] 



SCIENCE. 



865 



cle will require foui- entries, on an average 

 one according to the author, the others ac- 

 cording to the subjects treated of in the 

 paper. 



It is proposed also to print, at the head of 

 each of the cards or slips, distinctive sym- 

 bols to indicate the science and particular 

 sub-division of the science to which the 

 paper refers. 



There can be no doubt but that, to satisfy 

 the needs of workers in laboratories, the 

 plan of having a card catalogue of subjects 

 is by far the most satisfactory. A book 

 catalogue would be practically useless ex- 

 cept to a student looking up references for 

 historical reasons, and should, therefore, be 

 kept in a general library, and not in a 

 laboratory library. For the use of workers 

 in laboratories the subject card catalogue 

 would be of the greatest importance, as 

 everyone knows who has ever kept one. It 

 is of great use to the director of the labora- 

 tory in the saving of time and brain matter, 

 because he no longer needs to remember all 

 articles which have appeared, and to the 

 student or investigator in keeping him in- 

 formed of all that is going on in his particu- 

 lar line of work. From the standpoint, 

 then, of Physics there can be no doubt but 

 that it would be desirable for the Interna- 

 tional Committee to print all three cata- 

 logues, the book catalogue and the two card 

 catalogues ; and of these the card catalogues 

 should be kept, it seems best, in the labora- 

 tory itself, or at least in such a situation as 

 to be ready for use by all the students. 



Ko suggestions are asked by the Commit- 

 tee concerning the division of the sciences 

 or the classification proposed ; and, in fact, 

 this matter is of secondary importance. The 

 plan is to have the assistants and the clerks 

 in the Central OfiSce in London make a 

 division of the titles according to subjects 

 and to label the cards and slips in some 

 definite way ; so that anyone, although 

 ignorant of the subject-matter, can arrange 



the cards easily and quickly when they are 

 received. 



Each card in Physics is to be marked 

 with the letter ' D,' and each subject card 

 is to have, further, a number, such as 

 ' 5410,' which signifies the particular sub- 

 division to which the subject has reference. 

 In this particular case the 5 would indicate 

 the primary division, ' Light ;' the 4 the sub- 

 division, ' Polarization ;' the 10 the special 

 subject, ' Methods of Producing Polarized 

 Eadiation.' 



According to this system Physics is divi- 

 ded into seven ' primary divisions,' so- 

 called, namely: Bibliography and Dynamics; 

 Heat ; Mechanical and Thermal Effects of 

 Contact and Mixture ; Vibrations, Waves 

 and Sound ; Theories of the Constitution of 

 the Ether and of Matter ; Light, including 

 Invisible Eadiation ; Electro-magnetism. 



' Bibliography and Dynamics ' is sub- 

 divided into seven sections : Bibliography of 

 Physics ; Dynamics in General ; Dynamics 

 of a Particle and Eigid Dynamics ; Elas- 

 ticity ; Hardness, Friction and Viscosity ; 

 Dynamics of Fluids ; Measurements of 

 Dynamical Quantities. 



' Heat ' is divided into seven sections : 

 Temperature and Thermometry ; Calorim- 

 etry ; Determination of the Mechanical 

 Equivalent of Heat ; Fundamental Laws of 

 Thermodynamics ; Thermal Conduction and 

 Convection ; Changes of Volume and of 

 State (Experiment and Theory) ; Eadia- 

 tion. 



' Mechanical and Thermal Effects of Con- 

 tact or Mixture ' is divided into five sec- 

 tions : Friction ; Capillarity ; Diffusion ; 

 Transpiration and Mechanical Perme- 

 ability ; Imbibition and Surface Condensa- 

 tion of Gases ; Solution and Osmose. 



' Vibrations, "Waves and Sound ' is di- 

 vided into five sections : Theory and Obser- 

 vation of Harmonic Vibrations ; Theory of 

 Wave Motion ; Sound ; The Sensation of 

 Sound ; The Physical Basis of Music. 



