Evening star. [volume] (Washington, D.C.) 1854-1972, 1907-10-18
SCIENCE NOTES.

At the recent congress of school by
giene in London the committee appointed
to arrange for the next congress, to be
held in Paris in 1910, consists OF the fol-
lowing members: Great Britain-Professor
osler, DIR. Kerr, Mr.. White Wallis and
Mr.. Cloudesley Brereton. British col
onies-Sir John Cockburn, K.C.MG.
Switzerland-Dr. F. Zolhnger (Zurich).
France-Mr. sigalas CBordeaux). Prof.
Lefevre Oille) and Prof. Chabot Gyons).
Belgium-Dr. Decroby. Russia-Prof.
Chlopine. Portugal = Profs. Saccadura
and Curry Cabral. United States-Dr.
Walcott, DR.. Gulick, Prof. Da Costa.
The use of cement is now firmly es-
tablished in the construction of buildings
for domestic and commercial purposes.
The economies of this material are more
than manifest and It's solidity is hardly
to be questioned, although 1t has been in
common use but a comparatively few
years. There are any number of block
forming machines on the market and up
to short time ago these machines were
limited to the formation of blocks of diff
ferent kinds. The variety of design has
been limited to the imitation of the diff
ferent kinds of stone commonly used in
architecture. The different cuts, shapes
and finishes of granite and other stones
were cleverly followed. but recently there
lids Uteu d uSuudlio Aol SoulCSHih6 Aiol z
than this. and one or two firms have I'M
dertaken to produce molds for the forna-
ton of pillars caps. baluster posts and
similar designs. These molds are now to
be had by those engaging In the business
of making cement blocks, and with their
use 1t is possible to construct a build
ing of very pleasing lines. Heretofore
this has been rather difficult with the
limitations Of the square block, although
some architects have secured some very
49, = ~Nt,
ingenuity in the combination Of such
block shapes as were available.
A new camera shutter so equalizes the
exposure of the photograph plates that
all parts are properly acted upon by the
light. Heretofore it has been impossible
to obtain an exposure in which the fore
ground and the sky would both be prop
erly timed. The result Of this disparity
is that II the timing be right to properly
bring out the details of the landscape
the sky will be SO overturned that it
will be an UNMARRIED stretch of white, the
beautiful light and shade of the clouds
being lost entirely. Their presence does
from an artistic standpoint. and in order
to obtain the cloud effects 1t has been
heretofore necessary to proceed by one
of two methods, viz. the use of ray
filter or by double printing. The former
has the disadvantage of greatly prolong-
ing the time of the exposure, although
it is certainly effective in bringing out
the true color values Of the composition.
The double printing consists Of making
two exposures, one for the sky and one
for the foreground on different plates,
and a portion of each plate Is printed on
the sensitized paper. This requires skill,
and the operation consumes much time.
This disadvantage OF the camera has
been overcome by the recent invention of
a new camera by which the plate is prop
erly exposed in the making OF landscape
picture no matter what the conditions
of light might be. This shutter differs
from all others in that 1t has but a single
blade or leaf and this rises from the
bottom. moves up to the top and returns.
The picture in the camera is always re-
versed, that Is, the sky is at the lower
part, and this movement Of the shutter
gives a very short exposure to that part
of the view, while q longer one is given
to the foreground. 1t Is possible to reg
ulate this shutter so that the foreground
will receive full seconds exposure, while
the sky portion is exposed for an eighth
of a second. When this shutter is de-
sired for work where the operator de
sires to minimize a strong overhead light
it Is placed in front of the lens, where
it Is attached very readily by means o.
a clamp, especially designed for the pur-
pose. For ordinary work where an even
exposure is desired, as In some interior
views. the shutter is mounted between
the lens.