452 
moted to the head of the department of geol- 
ogy. At the same meeting Mr. Irving Per- 
rine, instructor in geology at Cornell Univer- 
sity, was appointed associate professor of geol- 
ogy. 
Dr. Percy KE. Raymonp, formerly of the 
Carnegie Museum, Pittsburgh, and more re- 
cently paleontologist to the Geological Sur- 
vey of Canada, has been appointed assistant 
professor of paleontology at Harvard Uni- 
versity, and curator of invertebrate paleontol- 
ogy in the Museum of Comparative Zoology. 
DISCUSSION AND CORRESPONDENCE 
NUMBER OF STUDENTS PER TEACHER 
To tHE Eprror or Science: In the January 
26 number of SCIENCE is a note on the “ Num- 
ber of Students per Teacher,” by Professor A. 
S. Hathaway, in which he says: 
It appears to me that the only correct way to 
determine the average number of students handled 
per teacher in any school is to divide the number 
of student hours per week by the number of 
teacher hours per week. 
This formula might simplify the mere 
mathematics of the situation, but it would 
most certainly fail to give just the informa- 
tion desired—the strength of the teaching 
force in an institution, or, in the words of 
Professor Hathaway, “the average number of 
students handled per teacher.” It is then far 
from being a correct way, to say nothing of 
the only correct way. 
The following illustration will show how 
the method suggested would miss the very pur- 
pose of our calculations. Suppose that a col- 
lege of 300 students, averaging 15 hours reci- 
tation per week each, has 5 instructors, each 
teaching 20 hours per week; then the result 
would be, according to the formula sug- 
gested, 
300 X 15 +5 XK 2045 ‘‘students handled 
per teacher.’’ 
Now, another college with the same number 
of students, each reciting also on the average 
15 hours per week, but with 10 teachers, each 
meeting classes 10 hours per week, would 
SCIENCE 
[N.S. Von. XXXV. No. 899 
show the same result; or a college of 225 stu- 
dents, averaging 20 recitations per week, with 
10 teachers, each having 10 classes per week, 
would show 45 “students handled per teacher.” 
Certainly the teaching forces of these schools 
would not be equally strong. 
It is not particularly the average number 
of students per class, or recitation, that we 
are after. Hven if this were our object we 
should find the matter more complicated than 
Professor Hathaway has supposed. Some 
“courses” require a proportionately larger 
number of recitations per hour’s credit than 
others. And how should we treat laboratory 
work, which can not with fairness be classed 
with recitations? Some laboratory courses 
require very little outside work, but more 
work in the laboratory, while others require 
a considerable amount. What complicates 
the matter still more, is the fact that in many 
cases student assistants direct such courses in 
large part while in others professors attend 
to the work themselves. These are only a 
few of the complications one actually finds. 
The class work does not afford the only op- 
portunity for the teacher to assist and stimu- 
late the student; and any scheme based upon 
class work alone would not only do an in- 
justice to some of the very best of our educa- 
tional institutions, but would also tend to 
emphasize unduly a practise that is doubtless 
already carried too far. 
JOSEPH PETERSON 
UNIVERSITY OF UTAH, 
Saut LAKE City 
ARE TEACHERS ENTITLED TO COMPLIMENTARY 
DESK COPIES OF TECHNICAL BOOKS ? 
Here is the teacher’s point of view: 
The texts which I am using are of no per- 
sonal benefit to me. JI am supposed to use 
the latest edition, and to change the text once 
in a while. I do not see how I can well afford 
to buy them. The publishers get big profits 
out of the students and can well afford to give 
a copy to the teacher, while, on the other 
hand, the teachers’ salaries are meager. And 
as to new reference books and practical engi- 
neering books, I can not always order them 
