hich has been stated under
the head of creosoting, that nothing but the impregnation with creosote,
and plenty of it, is an effectual protection against the _teredo_.
Numberless experiments have been tried abroad and in this country, and
always with the same result.

There are quite a number of other experiments which your committee has
learned about which are here passed in silence. The accounts of them are
vague, or the promised results of such slight importance as not to
warrant cumbering with them this already too voluminous report.

The committee also forbears from discussing the merits of the many
patents which have been taken out for wood preservation. It had prepared
a list of them, and investigated the probable success of many of them,
but has concluded that it is better to confine itself to the results of
actual tests, and to stick to ascertained facts.

Neither does the committee feel called upon to point out the great
importance of the subject, and the economical advantages which will
result from the artificial preparation of wood as its price advances.
They hope, however, that the members of this Society, in discussing this
report, will dwell upon this point.

We shall instead give as briefly as possible the general conclusions
which we have reached as the result of our protracted investigation.

DECAY OF TIMBER.

Pure woody fiber is said by chemists to be composed of 52.4 parts of
carbon, 41.9 parts of oxygen, and 5.7 parts of hydrogen, and to be the
same in all the different varieties. If it can be entirely deprived of
the sap and of moisture, it undergoes change very slowly, if at all.

Decay originates with the sap. This varies from 35 to 55 per cent. of
the whole, when the tree is felled, and contains a great many
substances, such as albuminous matter, sugar, starch, resin, etc., etc.,
with a large portion of water.

Woody fiber alone will not decay, but when associated with the sap,
fermentation takes place in the latter (with such energy as may depend
upon its constituent elements), which acts upon the woody fiber, and
produces decay. In order that this may take place, it is believed that
there must be a concurrence of four separate conditions:

1st. The wood must contain the elements or germs of fermentation when
exposed to air and water.

2d. There must be water or moisture to promote the fermentation.

3d. There must be air present to oxidize the resulting products.

4th. The tempe