Correspondence. 419 
aid, is a hindrance in the machine, such persons alleging that the great- 
er part of the heat is lost in the state of latent heat, and that there is a 
set-off for the rest in the resistance which the metallic network offers 
to the passage outward of the hot air. 
MM. Galy-Cazalat and Liais, who have come out as the opponents 
of Ericsson’s invention, do not appear to understand the true use of the 
Fegenerator, to which they attribute a uniform temperature after the 
column of hot air has deposited there its caloric, and deny wholly its 
away with the regenerator, and give, per horse-power, 40 square de- 
cimeters to the surface heated. ‘* This surface in the caloric engine,” 
Says he, “is so small and so highly heated that it allows two-thirds of 
the heat to escape uselessly into the atmosphere ; so that the economy 
due to the regenerator, were it real, should be reckoned only with ref- 
the sa 
plan of which is still kept secret; and it was afterwards abandoned for 
isdiuaiiaijdaiaaiamngt. 
_ * See this Journal, this volume, p. 106, 
