78
building in stone, and are still ignorant of the most rudimentary principles of this branch of constructive art. The old Roman arch which marks an era in the history of building has no place in Japan. There certainly exist at Nagasaki, Kagoshima and in other places in the south, several specimens of semicircular stone arches, but these were introduced by the Dutch residents and have never been largely adopted. In this also the Japanese have shewn a great want of appreciation of the art of building, and are behind their neighbours, the Chinese, in whose, country I understand miles of stone arches may be seen, some of which are of almost incredibly large span.
Such stone work as is executed in Japan is put together perfectly dry, and it is an extraordinary circumstance connected with this subject that the people appear to be quite ignorant of the cementing properties of lime or of the use of lime mortar.
The use of mortar dates from the period of the invention of the Roman Arch some centuries before Christ, and was commonly used by the Romans of those days; but even up to the present day, after some years of education by foreigners, Japanese workmen will persist in laying stones on top of one another without any substance between them to fill up irregularities or to cement one to the other. Solidity in their masonry is not considered necessary and the beds or joints of the stones are not made flat or even. The spaces between them are therefore large and are generally filled with pebbles which are all that keep the stones in their proper places. Not being acquainted with the use of common mortar it is unnecessary to say that they are also ignorant of the value of hydraulic mortar. The Romans also taught us a lesson in regard to this which I am astonished to say has not been followed even by ourselves to the extent which was possible. They mixed the lime with Puzzolana, or volcanic sand, which gave it the peculiar property of hardening under water; this mixed, with certain proportions of gravel, formed concrete which, being thrown into the sea between moulds, in a short space became so solid and hard
