Marcu 15, 1901.] 
effect he uses positives printed on glass and 
moderately illuminated before a specially 
arranged background. The details are set 
forth in a small pamphlet* which may be 
advantageously studied by any one who 
cares to employ the new method. 
It will be observed that the stereoscopic 
method gives the shapes of lunar features 
in terms altogether independent of those 
afforded’ by telescopic observation. The 
data furnished by the telescope serve 
through the principle of shadows; the 
data of the spectroscope serve through the 
principle of optical parallax. In the stereo- 
scopic view light and shadow join with 
local color in defining points and spots, and 
all points are thrown into proper relation 
through their parallaxes. 
x G. K. Givperr. 
A FURTHER STUDY OF THE UNIT SYSTEM 
OF LABORATORY CONSTRUCTION. 
Iv is desired to present a series of draw- 
ings with the necessary explanations to 
illustrate the practicability of designing a 
laboratory on a unit system. These draw- 
ings are the outcome of a somewhat careful 
study of the problem and of discussions 
with a number of experienced laboratory 
administrators. They seem to me to dem- 
onstrate the entire possibility of construct- 
ing a laboratory upon the unit system. 
In a previous article, which was published 
in the Philadelphia Medical Journal,+ it was 
maintained that the unit system of Labo- 
ratory construction offers real and very 
great advantages. The advantages are 
architectural, administrative and for the 
work of instruction. 
The architectural advantages are those 
of facility and flexibility of design, and 
those of convenience and economy of con- 
*De lemploi des photographies stéréoscopiques 
en sélenénologie. Extrait de l’annuaire de 1’Obser- 
vatoire royal de Belgique pour 1901. 27 pages. 
+ Vol. VI., p. 390, Sept. 1, 1900. 
SCIENCE 
- struction. 
409 
It is evident that if the essen- 
tial requirement is to provide a number of 
rooms of uniform and moderate size, abun- 
dantly lighted and conveniently accessible, 
then an architect has a comparatively sim- 
ple problem, which may be carried out in 
a great variety of designs, and may be 
readily adapted to special situations and 
conditions. Such a requirement leaves an 
architect great freedom as to the exterior 
of the building, which generally seems as 
important to the architect as the interior 
arrangements are important to the owners 
and users of a building. One indispensable 
exception to the exclusive adoption of the 
unit rooms will recur, in probably every case 
—namely, that of lecture rooms. As re- 
gards the construction, I am informed that 
it would cost less for a building on the unit 
plan than for one of equal capacity but 
with rooms of the customary irregularity 
of size. 
The advantages of administration are 
manifold. Most valuable will prove, I think, 
the possibility of changing the uses to which 
the rooms may be put, for not only may 
the use of a given room for one object or 
another of a given department be changed, 
but it may be transferred wholly to a dif- 
ferent department, for a unit room as pro- 
posed will be equally adapted to the needs 
of, for example, chemistry, botany, anatomy 
or physiology—its adaptation to the special 
needs of any of these sciences depending 
only upon the furniture put into it. Within 
a single department a unit room may be 
applied to many different uses. It will be 
of convenient dimensions for a class of ele- 
mentary study, a smaller class of advanced 
students, or a still smaller number of re- 
search men, or of assistants. It can be 
subdivided into two smaller rooms by tem- 
porary partitions. It will be convenient 
for collections, for a library or reading 
room, or for a small lecture room. The 
particular use of any room can be changed 
