APRIL 18, 1884.] 
have now, for the first time, a connected statement 
of the whole investigation, which lays a foundation 
for future extended work in the same direction. 
A casual reader would hardly be likely to appre- 
ciate the immense amount of labor involved in the 
research, both in observation and computation: but 
all acquainted with this sort of work will know that 
it must have been exceedingly laborious, tedious, and 
delicate ; and specialists will await with great inter- 
est the publication of the unabridged memoir, in the 
Transactions of the National academy of sciences, 
with all the original records and details of the obser- 
vations. 
—Ina paper published in Van Nostrand’s maga- 
zine, Professor Thurston introduces a report, by 
Messrs. Brooks and Steward, on tests of an Otto gas- 
engine made at the Stevens institute of technology 
in the spring of 1883. The machine was furnished 
by the builders, and was subjected to a careful test, 
determining the method of distribution of heat, in 
useful effect and in wastes. Earlier determinations, 
under the direction of Professor Thurston, had been 
made, with results, in one case, given in illustration, 
as follows: — 
Useful (dynamometric) work 5 . 14.27 
WOSSIRE CURTULT) EA ee 2 
Friction ofengine . . . erie Weaetriey «1, e4sL0 
Heat ‘ exhausted’ from engine 23.55 
Heat wasted by water-jacket . 46.90 
Loss by radiation, etc. . 10.76 
Total heat supplied . 100.00 
The consumption of fuel a evor twenty-one to 
twenty-four and a half cubic feet per horse-power and 
per hour. The friction of mechanism was four or 
five per cent of the total energy of the fuel, or about 
thirty per cent of the useful power. The water-j acket 
carried off from forty-five to fifty-five per cent of the 
heat of combustion. The engine delivered seven to 
nine horse-power. 
The trials of 1883, at the Stevens institute of tech- 
nology, were made with an engine rated at ten-horse 
power. The air and gas were both measured by 
meter, — probably the first time that this had been 
attempted. It wasfound that the real proportions of 
air and gas were not determinable, except by meter- 
ing both, as here done. The fact was proven that 
combustion continues, even after expansion has pro- 
gressed to a very considerable extent, —a fact that 
had been before suspected, but probably never before 
proven. The distribution of heat was as follows: — 
‘Indicated ’ work 17.00 
In exhaust. 15.50 
In water-jacket . 52.00 
Lost by radiation, etc. 15.50 
Total heat . a end ex td eee . 100.00 
In the ‘ indicated ’ sae are included useful work, 
and friction of engine, the latter amounting to about 
0.20 of the former. 
The cost of operation of the gas-engine is given at 
8.75 cents per horse-power and per hour, — consider- 
ably more than the steam or the hot-air engine, when 
working continuously; but the comparison is more 
favorable to the gas-engine for discontinuous work. 
SCIENCE. 
497 
The expense of the gas-engine will also be greatly re- 
duced by the introduction of special ‘ heating-gas,’ 
which can be supplied at one-half the cost of illumi- 
nating-gas. 
The report affords an unusually full collection of 
valuable data for use in the construction of the theory 
of the gas-engine. It is remarkably well worked up, 
giving the equations of the expansion-lines; compo- 
sition and specific heats of the gases; pressures, vol- 
umes, and temperatures at the various portions of 
the cycle; and all items of cost. 
— At the meeting of the Linnaean society of Lon- 
don, on March 6, Professor Cobbold gave a verbal 
account of a communication from Dr. P. Manson of 
Hong Kong, in which the author furnishes fresh evi- 
dence as to the réle of the mosquito considered as 
the intermediary host of Filaria sanguinis-hominis. 
Dr. Manson has verified his previous observations in 
the most complete manner, and he now recognizes 
and describes six well-marked stages of the Filariae 
whilst they are dwelling within the body of the insect. 
In the discussion following, Dr. T. R. Lewis con- 
firmed Manson’s statements in many particulars. 
—M. Tisserand, assisted by MM. Bijourdan, Cal- 
landreau, and Radau, issued on Feb. 15 the first num- 
ber of anew astronomical monthly, entitled ‘ Bulletin 
astronomique,’ to be published under the auspices of 
the Paris observatory. 
— Nature announces that at the final meeting, 
March 21, of the general committee of the Interna- 
tional fisheries exhibition, the balance of the funds 
was disposed of. The surplus amounts to over £15,- 
000; and of this, £10,000 were allotted to alleviate 
the distress of widows and orphans of sea-fishermen, 
while £3,000 were voted as an endowment to a society 
which is to be called ‘ The royal fisheries society,’ 
whose functions will be somewhat similar to those 
of the Royal agricultural society. The remaining 
£2,000 are kept in reserve. 
— For the purpose of a scientific inquiry into the 
amount and fluctuation of the rainfall in different 
parts of the world, A. R. Binnie, Town Hall, Brad- 
ford, Yorkshire, Eng., wishes to collect long and con- 
tinuous records of rainfall extending from as early a 
date as possible. 1°. The records should state the 
annual falls only, as taken year by year without a 
break, for periods of at least fifteen years; but the 
longest possible period is most desired. 2°. The name 
of the place of observation, with, if possible, the lati- 
tude and longitude, and its elevation above the sea- 
level, should be given. 38°. The total annual fall 
should be expressed in millimetres, English inches, 
or local or obsolete measures; but if in either of the 
latter, their equivalent in millimetres or English 
inches should be given. 4°. The name of the ob- 
server, or authority, or publication from which the 
record is obtained, should be given. 5°. The records 
should be from observations made at a single station, 
and should not be compiled from the records of two 
stations; but the greatest number of different records 
taken at different stations is desirable, to avoid local 
errors or peculiarities. 
