Evening star., 1896-12-05
NEW USE OF PHOTOGRAPHY.
Note Books With Intricate Formulas
Now Made for Engineers.

Note books with Intricate Formulas
Now Made for EnEincers.
From the New York Sun.
John W. Nystrom OF Philadelphia, a WELL
known civil and mechanical engineer once
said to his colleagues: Make your own
pocket book In giving this advice Mr..
Nystrom did not have in mind a receptacle
for money, but little volune usually car
ried about by engineers containing rules,
mathematical tables and formulas adapted
for immediate use. At first it was cons:d-
cred to be almost impossible for man 10
make a book of this kind. but now modern
science steps in, and every engineer can
make pocket hook for himself which will
invariably suit him better tnan anything he
could buy, because 1t may be made TO serve
him in the special branch Of engineering
" hich he practices.
Thus the civil engineer whose specially is
hydraulic rams and the flow of water In
channels is likely to find in his general
pocket book only few formulas for max
Ing the calculations he needs. Even If the
subject is treated more exhaustively. the
engineer may not be familiar with the sys-
tenn, so he does better IL he follows Mr.
Nystrom's advice Figure the thing out
for yourself, preserve the formula used and
when you have 1t to do again it will be
easy
But formulas accumulate rapidly. and any
engineer or astronomer engaged in active
being without an index, Is not of great
value. The problem that confronts him,
then, is how to bring this mass of matter
into some neat. compact and portable FORM
He may have hundreds Of formulas in al
zebra and calculus which, owing to their
length, he dare not copy, as that would be
conducive to errors.
There is some one who can copy them for
him. however, and that man has never
been known to make a mistake. He has
copied thousands Of finely printed pages re-
p!ete with intricate algebraical calculations
" here the omission of an accent would
spoil the whole result. He does his work
we'll and quickly, too. sometimes copying a
whole page in something less than a sec
ond. In short, he is infallible. That man
Is the photographer. and he has become
so popular of late among physicians, en-
gineers. lawyers and mathematicians that
special departments have been instituted
in many studios for wcrk of this sort.
For notebook OF this kind notes should
be made, not in script, but with a type
writer, one. of course. having a mathemat-
ical keyboard, including the signs Of addi-
ton, multiplication. subtraction and di-
vision. The size of the paper used should
depend upon the desired dimensions of the
volume. Sheets by 10 inches reduce pho
Geographically to by inches nicely. Pure
white paper Is the best, and it should not
be folded, otherwise the creases will show
in the photograph. When the page of mat
ter Is once recorded on the Photographic
plate. as many copies as are desired may
be printed on blue print or other prepared
paper without the slightest chance of error
These different prints are then bound to-
gether, and behold, a book. or several
books, for that matter. If so desired. 1t
sometimes happens that a good mathemat-
ioal table IS found in some ole volume now
out of print. This may be photographed
reduced or enlarged to any desired size, and
Incorporated in the book. The copy so
made is bound to be truthful. which might
not be the case If 1t had been made with a
pen or put into the hands of printer.
All engineer owning his camera can make
his own pocket book for about ten cents a
page. which is about Is cents below the
price charged by photographers. Some lit
tie experience is necessary in order to get
the right time of exposure. as well as the
right size of lens, which must not have too
much curvature.