The San Francisco call., 1906-05-06

pie who are awaiting news OF the fate
OF valuable documents they have
stored In safes and bank vaults and
who are fearful IN some instances that
heat may have 30 charred the docu-
ments as to make the work Of de-
ciphering them difficult have written
to Professor Edmund O'Neill, dean Of
the college Of chemistry at the State
University, about their fears.
In reply to these inquiries Professor
O'Nein today issued statement deal
ing with the proper methods to be OBJ
served In handling safes that are as
Yet unopened and documents that have
been charred and rendered partly illeg-
ible by great heat Professor O'Neills
announcement is as follows:
1.-THE following Suggestions are made
In the hope that they might be Of some
value to persons who find valuable
records partially destroyed by fire.
'The destruction of organic matter
by fire is dependent upon two points:
Increase of temperature and the pres
ence of air or oxygen. If excess OF air
be present on the elevation of tenn
perature TO igniting point the whole
mass viii burn UP completely. II the
air be kept out an elevated tempera-
ture may be maintained for some time
and the paper will be slowly destroyed
Volatile matter Is given off and finally
the residue of carbon, more less pure,
Is left behind. This carbonaoeou resi-
due Is very friable and difficuit to
handle. This temperature of de-
composition is not very high and varies
according to the quality of paper. It
begins below 500 degrees Fahrenheit
and becomes more rapid as the tenn
perature increases. But a compara-
lively low temperature long continued
will destroy the paper as effectually rs
a higher temperature.
COOL THE SAFE.
The safety OF paper inolosed ia So
called flreproof safes depends upon the
heat Insulation, and the more non-con-
Quoting and the thicker the layer of
hreproof material the longer It will
take to transmit the heat to the inner
chamber. But IL the safe is covered
with hot or glowing material It IL SIM
ply a question OF time when the heat
VIII be transmitted into the inner
chamber and causs the paper to de-
compose.
'The sooner the safe can be removed
from its hot bed and cooled to normal
temperature the better It Is for the
contained papers. The better the safe
the more slowly it will cool, and such
safes should be left much longer be-
fore opening than the small and poorer
qualities. II air be admitted before
the temperature has sunk below the
point of ignition the papers viii in
stantly take fire when exposed to a
current OF air. The temperature of ig-
milton is somewhere In tho neighbor-
hood OF 300 degrees Fahrenheit and Il
it is not certain that the interior of the
safe is cooled below that temperature
It viii be perilous to open 1t
''The cooling may be hastened by the
withdrawal OF the safe from its hot
bed. Covering 1t with sacks or cloth
or other porous material and pouring
water upon It will also hasten the cool
ing to q great degree. The ignition
may also be stopped by preventing the
access OF air. but methods for doing
this would be cumbersome to carry
out. The steam from the wet sacks
would probably be the most efficient
way TO prevent the access OF air. When
the interior Of the safe is cooled below
the igniting point there is no danger
in opening and removing the docu-
ments.
"If the papers are charred so that
the writing is apparently illegible. the
sheets may be removed one by one and
laid on q plate of glass. frequently
the writing may be observed by hold
ing the sheets at a certain angle and
the reflection Of light from the ink
surface viii be distinct. This Is some
times Increased by moistening the pa
per with water. Chemical methods Of
rendering the writing visible may be
employed In certain cases.
CHEMICALS TO BE USED.
links are OF two classes: First, where
metallic salts are used, and second.
where organic coloring matters. mainly
aniline bodies, are employed. Inks Of
the first class are usually tannates or
sallates OF Iron or logwood bichro-