50 ANNUAL OF SCIENTIFIC DISCOVERY. 



there being no less than three feet of evaporating surface for every 

 foot of furnace bars. The process of blowing off was provided for 

 by arranging, under the flues and furnaces, large water spaces, as 

 reservoirs for the collection and blowing off of brine, and other 

 deposit. Proc. Inst. Civ. Eny. 



DIAPHRAGM STEAM GENERATOR. 



THE principle upon which this steam generator, invented by M. 

 Boutigny, is based, is that " bodies evaporate only from their sur- 

 faces." This being received as an axiom, it must necessarily follow, 

 that in the construction of steam boilers, either the evaporating sur- 

 face of metal should be extended to its utmost limit, or the water 

 should be so divided, and its evaporating surfaces be so multiplied, as 

 to arrive at the same end, of obtaining the greatest amount of steam, 

 by the expenditure of the least amount of fuel. The steam generator 

 is described as consisting of a vertical cylinder of wrought iron, 25 

 inches high, by 12| inches diameter ; the base terminating in a hemi- 

 spherical end, and the upper part closed by a curved lid, upon which 

 w r as attached the usual steam and safety valves, feed, steam, and other 

 pipes, &c. The interior contains a series of diaphragms of wroifght 

 iron, pierced Avith a number of fine holes and having alternately con- 

 vex and concave surfaces. They were suspended by three iron rods, 

 at given distances apart, in such a manner as not to be in contact with 

 the heated exterior, or shell of the boiler. When any water was 

 admitted through the feed-pipe, it fell upon the upper (convex) disc, 

 which had a tendency to spread it to the periphery, the largest quan- 

 tity falling through the perforations in the shape of globules ; the 

 second diaphragm, being concave, tended to direct the fluid from the 

 circumference to the centre, and so on, until, if any fluid reached the 

 bottom of the cylinder, it mingled with a thin film of water, in a high 

 state of ebullition, that being the hottest part of the boiler. It 

 appeared, however, that in its transit through these diaphragms, the 

 water was so divided, that, exposing a very large surface to the caloric, 

 it was transformed into steam with great rapidity, and with great 

 economy of fuel. The boiler described has been worked for a long 

 time at Paris with great success, giving motion to a steam engine of 

 two horse-power. The consumption of coal is stated to be very 

 small; 789 pounds of water having been converted into steam by 182 

 pounds of coal in nine hours, under a pressure of ten atmospheres. 

 The chemical part of the question has been carefully examined, and 

 it has been shown that at that temperature the iron was exactly in the 

 best condition to bear strain. M. Boutigny has only proposed this 

 system for small boilers, and under circumstances of wanting to obtain 

 a motive power in situations of restricted space, and where first cost 

 was a great object. Cicil Engineer's and Architect's Journal 



