MOARURE 
241 

THURSDAY, JANUARY 26, 1871 

PHYSICAL LABORATORIES 
T is well known that chemistry can be taught far better 
by a laboratory in which the student performs the 
various experiments, than by any system of lectures. 
Now, although for many years physicists have been in the 
habit of instructing their special students and assistants 
in this way, yet it is only recently that the same plan has 
been tried with large classes in physics. One of the first 
institutions to attempt this method, in America at least, 
was the Massachusetts Institute of Technology in Boston ; 
and asI find many colleges here establishing physical 
laboratories, I trust that our experience may prove of 
some interest. The great difficulty is to enable twenty or 
thirty students to perform the same experiment without 
duplicating the apparatus, and to avoid the danger of 
injury to delicate instruments. Our plan is this :—Two 
large rooms (one nearly a hundred feet in length) are 
fitted up with tables, supplied with gas and water, some- 
what like a chemical laboratory. On each is placed the 
apparatus prepared for a single experiment, which always 
remains in this place, thus avoiding the danger of breaking 
it in moving. A full written description is also given of 
each experiment, pointing out the proper precautions to 
avoid error or breakage. Near the door is an indicator 
or board containing the names of the experiments, and 
opposite each is placed a card bearing the name of the 
student. When the class enters the laboratory, they go 
to the indicator, and each member notices what experi- 
ment is opposite his name ; he then goes to the proper 
table, reads the description, and performs it. He next 
reports his results to the instructor in charge, and if they 
are correct, his card is moved to some unoccupied place, 
and he proceeds as before. Care is taken that the number 
of experiments shall exceed that of students, and there is 
therefore no delay. The instructor in the mean time is 
enabled to pass from student to student and to see that 
no errors are committed. As quantitative work is far 
more valuable than qualitative, most of our experiments 
are of the former kind, and the student learns to measure 
physical constants and to verify laws numerically. For 
example, in one experiment a steel bar is supported on 
knife edges, and a weight is applied at the centre. The 
flexure is then measured by a micrometer screw, the exact 
point of contact being determined by including the screw 
and bar inthe circuit of a battery and galvanometer. After 
making a number of experiments with various weights, the 
student constructs a curve in which ordinates represent de- 
flection, and abscissz weights applied. The law of elasticity 
shows that this curve should be a straight line, and the 
close agreement is convincing proof to the student of its 
correctness. In the same way the law of the conjugate 
foci of lenses is tested, and the observed curve compared 
with that deduced from theory. Some experiments are 
introduced to accustom the student to general methods of 
research, such as the computation of probable error by 
least squares, various forms of interpolation, &c. The 
graphical method is largely used, as it at the same time 
enables the student to take in all his observations at one 
glance, while the instructor can constantly tell how 
VOL, III. 


carefully the work has been done. For the microscope 
a few objects are selected to show certain general methods 
of using this instrument, as one requiring a diaphragm, 
a second oblique illumination, and so on. Again, the 
student views by polarised light such objects as unannealed 
glass, crystals, designs in selenite, and studies the effects 
produced by various agencies. By thus handling the 
instruments he acquires a facility in using them and 
comprehension of their construction which he could 
never obtain from lectures. The excellence of the work 
done by many of the students led to the hope that 
valuable results might be attained by assigning to different 
students the experiments in a research, taking care that 
each should be repeated several times by different 
individuals. These results, if concordant, would be much 
more conclusive than those obtained by a single experi- 
menter, since they would be free from all personal bias. 
In this way some interesting results have been attained 
on the foci of lenses placed obliquely, the flow of air 
through straight and curved tubes, and other similar 
subjects. Photometry and electrical measurement seem 
especially suited to, this purpose, and the application 
of the latter subject to submarine cables would be both 
interesting and instructive to the student. During the 
winter time of 1869 and 1870 about sixty students worked 
in one laboratory, so that the experiment was tried on 
a sufficiently large scale to enable us to speak with con- 
fidence of its success. We found the system described 
above worked well, the students were interested in the 
subject, and obtained results of considerable accuracy. 
The loss by breakage was exceedingly small, and the 
current expenses insignificant compared with a chemical 
laboratory, since there is but little consumption of the 
materials employed. 
There are now in America at least four similar labo- 
ratories either in operation or preparation, and the chances 
are that in a few years this number will be greatly in- 
creased. The value of a knowledge of physical manipula- 
tion is becoming daily better appreciated, and it is evident 
that instruction of this kind can be properly given only 
in a physical laboratory. 
EDWARD C. PICKERING 

SCIENCE TEACHING IN PRIVATE SCHOOLS 
A WRITER of the early part of last century defined a 
philosopher as one “ whose trade was to do nothing, 
and to speculate upon everything.” While philosophers 
were so lightly esteemed, it is no matter of surprise that 
philosophy was little cared for as a part of education. But 
such a definition as the above would not now be generally 
accepted even by the unscientific public. All are begin- 
ning to see that it is to Science they are indebted for so 
many of the comforts and advantages of civilisation, yet 
to the many is Science a mystery and closed book. And 
one great cause of this we believe to be, because it is not 
taught in our schools. 
We purpose, in the present article, to speak only of 
private schools. If a visitation were to be made of such 
schools in England, we venture to say that very few, com- 
paratively, would be found, in which Science, in any of 
its branches, is made a subject of regular education. The 
boys of most schools would be classed by the masters 
O 
