230 
that the new star had put on the appearance presented ordinarily 
by the so-called planetary nebulz. 
“Of all the lines chronicled by Cornu and Vogel during its 
stellar stage, only one remained, that, namely, which the latter 
observer showed to be constantly increasing in brightness while 
all the rest were waning, and which, moreover, was coincident in 
position in the spectrum with that observed in the majority of 
the nebulz. 
0 
a 
| 
o 
6.—Vog-l's sz 
from a scientific point of view, although no word would be better 
to describe it in its popular aspect. ‘The word is a misnomer for 
this reason. If any star, properly so called, were to become 
“fa world on fire,” were to ‘*burst into flames,” or in less 
poetical language, were to be driven either into a condition of 
incandescence absolutely, or to have its incandescence increased, 
there can be little doubt that thousands or millions of years 
would be necessary for the reduction of its light to the original 
intensity. 
Mr. Croll has shown that if the incandescence observed came for 
instance from the collision of two stars, each of them half the | 
mass of the sun, moving directly towards each other with a 
velocity of 476 miles per second, light and heat would be pro- 
duced which would cover the present rate of the sun’s radiation 
for a period of 50,000,000 years. 
A very different state of affairs this from that which must 
NATURE 
| Kuly 8, 1886 
The observations of such rare phenomena as the so-called new 
stars are of such vast importance, and will no doubt ultimately 
provide us with a clue to so many oth of a different order, 
that we may well congratulate ourse that this Nova was so 
well watched, and tt is such perfect completeness and 
unity ia the chain of recorded facts. 
It should have been perfectly clear to those who thought about 
such matters that the ar in such a case is a misnomer 
W 
Dec. 14. 
1877. 
Jan. x. 
Feb, 2. 
Mar. 2. 
a 
cctrum of Nova Cygni. 
have taken place in any of the Novas from the time of Tycho to 
our own, and the more extreme the difference the less can we 
be having to deal with anything like a star properly so called. 
The very rapid reduction of light in the case of the new star 
in Cygnus was so striking that I at once wrote to Mr. Hind to 
ask if any change of place was observable, because it seemed 
obvious that if the body which thus put on so suddenly the 
chromospheric spectrum were single, z¢ might only weigh a few 
fons or even hundre hts, and being so small might be very 
neat us. No motion, however, was perceptible, and Dr. Ball 
has since stated that he could detect no parallax. 
We seem driven, then, from the idea that these phenomena 
are produced by the incandescence of large masses of matter, 
because if they were so produced, the running down of brillianey 
would be exceedingly slow. J. NorRMAN LocKYER 
(Zo be continued.) 
FLAME CONTACT, A NEW DEPARTURE IN 
WATER HEATING? 
le is my intention to prove to you on theoretical grounds, and 
also by experimental demonstration, in such a manner as 
will admit of no possible doubt, that the present accepted 
system of water heating, by gaseous or other fuel, is a very 
imperfect means for an end, and is, both in theory and practice, 
essentially faulty. My statements may appear bold, but I come pre- 
pared to prove them in a manner which I think none of you will 
question, as the matter admits of the simplest demonstration. I 
will, in the first place, boil a specified quantity of water ina 
flat-bottomed vessel of copper; the time required to boil this 
you will be able to take for yourselves, as the result will be 
visible by the discharge of a strong jet of steam from the boiler. 
* A Paper read by Thomas Fletcher, F.C.S., at tke Gas Institute Meeting, 
London, June 9. 
I will then take another copper boiler of the same form, but 
with only one-half the surface to give up its heat to the water, 
and will in this vessel boil the same quantity of water with the 
same burner in a little over one-half the time, thus about 
doubling the efficiency of the burner, and increasing the effective 
duty of the heating surface fourfold, by getting almost double 
the work from one-half the surface. 
The subject is a comparatively new one, and my experiments 
are far from complete on all points, but they are sufficiently so 
to prove my case fully. As no doubt you are all aware, it Is 
not possible to obtain fame contact with any cold, or compara- 
tively cold, surface. This is readily proved by placing a vessel 
of water with a perfectly flat bottom over an atmospheric gas- 
burner: if the eye is placed on a level with the bottom of the 
vessel a clear space will be seen between it and the flame. I 
cannot show this space on a lecture-table to an audience, but I 
can prove its existence by pasting a paper label on the bottom 
