482 KANSAS CITY REVIEW OF SCIENCE. 
boiler, in front and in rear of the ordinary bridge-wall. They have been of con- 
siderable value on locomotive boilers, though some claim they are liable to warp 
some of the boiler plates. My own knowledge does not agree with this opinion. 
loth. Doors. These are sometimes perforated, slit or hanging, and seem 
to be of advantage in some cases, admitting air into the fire-box itself, as do all 
the air-jets, wet or dry. 
iith. Mixed Devices. These are compilations of ideas taken from two or 
more of the above designs. They are rarely worked upon by men who have in^ 
ventive genius. 
1 2th. Petroleum Jets, These have been tried in several places, but, so far 
as I am aware, with but poor success. Steam has to be raised in the boilers be- 
fore they can be applied. 
13th. Smoke Burners. These are devices which return the smoke under- 
neath the fire bars. I am not particularly impressed with them, as I believe 
them to be valueless. 
14th, Boiler Setting. This, as been said before, is a great item for consid- 
eration under this subject, and may be spoken of as devices .built for economy of 
fuel by |;iving a very large space for the perfect intermingling of the gases of the 
coal and of the atmosphere. 
In conclusion I wish to state that the matter of smoke prevention is by no 
means yet thoroughly grasped, but may soon be if we obtain, along with the 
above considerations a matter which I thus expressed to the Engineers, "Intelli- 
gence in front of our boilers." 
Permit me quote here a statement made by Wagner, with which I thoroughly 
coincide, as it bears out the remarks I have but poorly made above: "As re- 
gards smoke consuming and smoke preventing apparatus, it is only too evident 
that most of these do notanswer the purpose so completely as might be expected. 
Practical experience has, however, taught that if the conditions of complete com- 
bustion are well attended to in construction of the furnace, with proper manage- 
ment and regular mode of stoking, adequate supply of air, and the application of 
the well-known means of preventing loss of heat by radiation, with coal, peat, 
or any other fuel, the combustion may be conducted so as to be smokeless ; and 
at the same time the fuel thoroughly utilized." 
Medical Department of Kansas City University, 
Chemical Laboratory, Nov. 13, 1883. 
THE PHILOSOPHY OF FLUXES. 
The rationale of fluxing brings us face to face with a wide-spread popular 
fallacy that has remained undisturbed and unrefuted (so far as we know) by any 
of our teachers of modern science. Workmen generally believe that by adding 
what is called a flux to a melted or melting metal, the metal is made to melt at a 
lower temperature, or that being melted, the flux renders the metal more fluid. 
