Aueust 11, 1899. ] 
anatomy with zoology, and of pharmacology 
and pathology with physiology. 
3. The schedule of classification for pure 
mathematics appears quite satisfactory. 
Defects, if any exist, are rather trivial and 
relate to details of nomenclature. I would 
suggest, however, under 0870, p. 2, the in- 
elusion of ‘ theory of errors’ before ‘com- 
bination of observations. ’ 
4, The schedule of classification for me- 
teorology seems disproportionately ex- 
tended. 
5. The classification for physics, if it 
should ultimately include mechanics, ought 
to be rearranged in many important re- 
spects. 
a. More importance should be given to 
pure kinematics and kinematical prin- 
ciples. 
b. Following Thomson and Tait, dynam- 
ics should be divided into statics and 
kinetics ; so that, for example, an entry 
with reference to flexible strings would in- 
dicate whether the case considered is static 
or kinetic, or both. 
ce. The entry under 0110, p. 2, for ex- 
ample, should be theory of force, momen- 
tum, impulse, energy and work. And 
under 0120, the statement should be: Prin- 
ciples of statics and kinetics, Differential 
equations of kinetics. Or, if more detail is 
desired, it should be: Principle of d’Alem- 
bert, virtual work, Lagrange’s method, 
least action, Differential equations of kinet- 
ics. 
d. Under 0250 there should be included 
the important sub-division of kinetics of 
plastic or non-rigid bodies. 
e. Under 0515 hydrodynamical should be 
replaced by hydrokinetic and 0520 should 
read: Rotational, or vortex motion. Vor- 
tex atoms. 
6. Many other criticisms concerning mat- 
ters of detail with reference to the divisions 
of physics might be submitted. So many 
ehanges in the proposed schedule seem de- 
SCIENCE. 
169 
sirable, however, that it may be wise to 
submit the matter to a sub-committee of 
experts. 
R. 8. Woopwarp. 
E. CRYSTALLOGRAPHY; G. MINERALOGY. 
I susmir the following suggestions as to 
the proposed schedules in Crystallography 
and Mineralogy: 
1. The division 2000, ‘Applied Crystal- 
lography,’ I do not think a good one. It 
does not suggest to me the sub-divisions, 
and I suggest ‘Crystal Structure and 
Growth,’ to include 1400, 2200, 2300 and 
2400 and that 2100 pass under Geomet- 
rical. 
2. Under Optical Crystallography (4000) 
the sub-division 4200 is overworked, and 
the sample references on the next page show 
it is made to cover discussions of methods 
of optical measurement, like that of Wal- 
lerant. I favor, including under 4000, all 
optical measurements and replacing 4200, 
or rather supplementing it, by a division 
into say: Refraction in Isotropic Crystals, 
Double Refraction in Uniaxial Crystals, 
Double Refraction in Biaxial Crystals. 
3. In Mineralogy I see no reason why the 
term General Mineralogy should cover so 
much. Separate divisions might well be 
made of (a) Microscopic Study of Minerals 
in Rocks, (b) Genesis and Alteration of 
Minerals, (c) Economic Mineralogy, (d) 
Artificial Minerals (or Synthesis). 
I favor the plan of printing both stand- 
ard sizes of card. It cannot greatly in- 
crease the expense, and will enable sub- 
seribers to choose the size already used by 
them. We have about 20,000 references on 
the smaller card. 
ALFRED J. Moszs. 
F. CHEMISTRY. 
I wave read very carefully the proposed 
schedule of classification for chemistry of 
the International Catalogue Committee, and 
