1865.] 11 [Trippel. 



The most essential desiderata for a perfect combustion and the 

 highest possible useful effect are, according to Mr. Schinz, 



First. Stochiometric proportioning of air and gases. 



Second. Sufficient contact surface between air and gas, and diffe- 

 rent velocities for each of them. 



Third. Compression of the mixed gases and air at the moment of 

 combustion. 



Fourth. Some criterion, whereby to determine whether or not a 

 perfect combustion takes place. 



It is hardly necessary to mention that, in order to make these 

 points, the chemical composition of the fuel must be well known ; 

 and that exact calculations have to be made with regard to all di- 

 mensions of the furnace. The rules and regulations by which to gain 

 these results, and the peculiar construction of the furnace, form the 

 chief points which distinguishes Mr. Schinz's system from others. 

 His furnaces were rewarded with the prize medal in the late London 

 Exhibition, and have since been patented in Europe and the United 

 States. Wherever they have been in use, they have given satisfac- 

 tion in every respect. 



As already observed, the present descriptions and drawings repre- 

 sent a reheating furnace, of the form and size of those built and used 

 at the Bethlehem Iron-works, by John Fritz, Esq., superintendent 

 of the establishment. They have the advantage of combining the 

 most approved form with carefully designed gas-generators for an- 

 thracite coal. 



Compared with the present consumption of coals in well-constructed 

 furnaces, the gas-heating system would save about 26 per cent, on 

 fuel, and allow the use of small coal, such as chestnut in the place of 

 lump, or lump and pea coal in equal parts. Another very considera- 

 ble advantage is the absence of ashes in the hearth, which often pre- 

 vents a perfect welding, and produces an inferior quality of iron. 

 This circumstance alone is doubtless, a sufficient inducement for the 

 introduction of the gas-heating form of furnace, as the evil influ- 

 ence of cinders is especially felt when fan-blowers are employed, and 

 when large plates of a faultless quality have to be produced. It is 

 further evident, that the gas furnaces will diminish the loss of metal 

 by preventing its oxidation or burning ; while the system admits 

 equally, when so desired, an excess of air, and thereby a powerful 

 oxidation, which, especially during a certain period in the puddling 

 furnace, will assist in expelling silicium, phosphorus, and sulphur. 



In presenting the great advantages of converting fuel into gas be- 



