PREFACE, The author trusts that this little handbook will fill a gap in the literature associated with the subject of Heating and Ventilation, though it will be recognised that the treatment of these two all-important subjects is not the direct purport of the present work. For, in the aspects of supplying heat in the one case, and of renewing the supply of air in the other, there is, indeed, no lack of books, but a work specifically dealing with the conduits for conveyance of the products of combustion from the grate to the external air seems to have long awaited production. And even now, far...