| and physicists. The proof o 
“which, the. genius 
tis will be seen in that laborious 
werk” ssiz inaugurated and which pre- 
fxthe depaytments included, Natural History 
' ng essentially descriptive sciences, are less fitted 
for the -elassifieataon of the subjects included, than the more 
abstract or logieg:inathematical-and plrysical sciences. A logical 
arrangement by stbjects, at least for Natural History, will scarcely 
a's 
pow be proposed by those interested, though it is possible that 
Exggelman’s Bibliography of Natural History which distributes - 
authors alphabetically under a limited number of general. heads, 
may yet serve as a model for indexing papers or memoirs in the 
same field. —« ‘ 
In proceeding to examine somewhat the subject of an index of 
all original papers in mathematics and physics, it may be well 
briefly to state the circumstances which have led me to consider it. 
As an Assistant in the Coast Survey, I had on several occasions to 
make special investigations, in which it was desirable to examine 
all good relevant authorities and original memoirs.. How to do 
this was the question. 'To range over series after Series, index 
after index from beginning to end, would surely bring to light all 
such papers. But this is a labor of truly appalling magnitude and 
not to be thought of for each minor research. It only remaine 
to start with such papers as I chanced to know of, or could find 
by the few indexes of series at my command. ‘hen following 
up all the references which could be gleaned from these sources, 
I could go on till they were exhausted. By that time any man of 
moderate patience would himself be exhausted, and indisposed to 
beat up, for farther game. Yet what guarantee is there in this pro- 
cess that the very best papers may not entirely escape one’s knowl- 
edge. I found from experience just this result; nor do 1 suppose 
that any person can be sure of having examined all those printed 
rs on a given subject of physical science, which are essential 
to a full comprehension of its history and development. He may 
find a vast deal more than he likes to read and yet leave the best 
of all unknown. ‘This is peculiarly true of those just entering 
on a career of research. Veterans bear in their memories some 
traces of the leading papers published during their lifetimes, on 
all subjects even likely to enlist their activity. But the neophyte 
has no such aid, and does not even know how to get at the most 
accessible memoirs. A great loss of time in turning over leaves 
for the want of specific references is common alike to young and 
old. Thus for instance when I wished to find all the published 
descriptions of automatic tide guages, I spent a great deal 0 
time to find what could be read in five minutes, and am by no 
