PREFACE. The following brief treatise was translated without abridgement from Nouvelle Mecanique Industrielle: M. LEON POCHET. It first appeared in its present form in Van Nostrand's Magazine for March and April, 1877. The literature bearing on the subject of the Injector is not abundant, and to many engineers the philosophy of the action of the apparatus is obscure. In view of the fact that uses for the Injector have been devised other than the feeding of boilers, is judged to be a sufficient reason for the preparation of this little work. STEAM INJECTORS. GENERAL THEORY OF STEAM INJECTORS. It is some years since M. Giffard introduced the injector apparatus which bears his name and which filled the scientific world with profound astonish ment. This ingenious apparatus, in which a jet of steam heading out of a boiler enters into the same boiler bringing with it a quantity of additional water, seems to proceed in accordance with a philosophical law contradictory to the ordinary laws of physics. It was in appearance a sort of perpetual motion. If the mechanical properties of heat had been better known, nothing would have appeared more simple. M. Reech, published, in 1858, (in the memorial du Genie Maritime), a theory |