larger manufacturers of roofing paper, in the presence of experts,
architects, and others, embracing the most severe tests, and it was
fully proved that the tar paper roof is as fireproof as any other.
These experiments were made in two different ways; first, the
readiness of ignition of the tar paper roof by a spark or flame from
the outside was considered, and, second, it was tested in how far it
would resist a fire in the interior of the building. In the former
case, it was ascertained that a bright, intense fire could be kept
burning upon the roof for some time, without igniting the woodwork of
the roof, but heat from above caused some of the more volatile
constituents of the tar to be expelled, whereby small flames appeared
upon the surface within the limits of the fire; the roofing paper was
not completely destroyed. There always remained a cohesive substance,
although it was charred and friable, which by reason of its bad
conductivity of heat protected the roof boarding to such an extent
that it was "browned" only by the developed tar vapors. A fire was
next started within a building covered with a tar paper roof; the
flame touched the roof boarding, which partly commenced to char and
smoulder, but the bright burning of the wood was prevented by the
air-tight condition of the roof; the fire gases could not escape from
the building. The smoke collecting under the roof prevented the
entrance of fresh air, in consequence of which the want of oxygen
smothered the fire. The roofing paper remained unchanged. By making
openings in the sides of the building so that the fire gases could
escape, the wood part of the roof was consumed, but the roofing paper
itself was only charred and did not burn. After removing the fire in
contact with the paper, this ceased burning at once and evinced no
disposition whatever to spread. In large conflagrations, also, the tar
paper roofs behaved in identically a similar manner. Many instances
have occurred where the tar paper roof prevented the fire from