_—_ 
April 20, 1871] 
NATURE 4 
495 

ECONOMIC ENTOMOLOGY 
= Royal Horticultural Society has just offered the 
following prizes for collections of Economic Ento- 
mology :— 
_ 1. A prize of ro/. for the best collection of British 
insects injurious to any one plant, as the oak, pine, 
cabbage, wheat, &c. (the choice of the plant to be left to 
the competitor). The insects to be shown as much as 
possible in their various stages of development—eggs, 
larva, chrysalis, and perfect insect. In judging, a pre- 
ference will be given to those collections which most 
successfully illustrate the life history of the insect, and 
exhibit the mischief done, whether shown by specimens, 
drawings, models, or other means. Examples of the 
application of drawings, models, and specimens to this 
purpose may be seen in the Society’s collection in the 
South Kensington Museum. 
2. Asecond prize of 3/. for the second best collection. 
3. A prize of 5/. for the best miscellaneous collection 
of any branch of British Economic Entomology, similarly 
illustrated. 
4. Asecond prize of 2/. for the second best collection. 
The collections to be sent to Mr. James Richards, 
Assistant Secretary, Royal Horticultural Society, on or 
before the 1st of May, 1872, each collection bearing a 
motto, and a separate sealed envelope, with the motto on 
the outside, and the name of the competitor inside. 
The Society is to be entitled to take from any of the 
collections sent in, whether successful or not, whatever 
specimens or illustrations they may choose, at a price to 
be fixed by the judges. 
The judges to have power to refrain from awarding the 
prizes, should the collections seem not worthy. 

SCIENCE TEACHING IN ORDINARY 
SCHOOLS 
% PLAN for teaching the Natural Sciences in ordinary 
schools has been submitted to the School Board for 
London by Mr. J. C. Morris. The following are stated 
by the Fournal of the Society of Arts to be the principal 
points of the proposed system :—Subjects—chemistry, 
heat, light, sound, electricity, magnetism, telegraphy, 
mechanics, hydrostatics, steam engine, &c.; geology, 
metallurgy, botany, zoology, animal physiology, health, 
&c A committee should be formed to select, revise, and 
compile a complete set of suitable text books, which should 
bear their sanction, and be then published in the cheapest 
possible form. There should be a depdt to provide 
apparatus at a cheap rate, a complete set of which, suffi- 
cient to illustrate the sciences mentioned, would not cost 
more than 100/., and should be divided into ten cases of 
to/, each, a case to be complete for one or two subjects. 
The teacher should be a visting one. He could attend 
from two to three schodls per day, and give from one to 
two hours’ instruction in each, during two days in the 
week. The instruction to be given in a separate apart- 
ment, if there be one ; or, if not, at such a time as would 
not interfere with ordinary school business. A single 
school teacher could thus attend from six to nine schools 
weekly, if sufficiently near each other, and get through at 
least three or four subjects annually, so that in two or 
three years he would have completed the full course in 
each school. 
There should be an institution where teachers would 
have an opportunity of acquiring a practical know- 
ledge of their profession, and affording a means of 
testing their qualifications. A more economical way, 
however, would be for each teacher to have an 
assistant, by which method a nucleus of teachers would 
soon multiply into a goodly number. | In conclusion, 
Mr. Morris advocates periodical examinations, with a 

regular system of rewards; and, in reference to funds, 
he thinks that the teachers and inspectors might be sup- 
ported either by Government or subscription, the appa- 
ratus to be supplied by Government at reduced rates. 
Schools should fix a small fee for attending the class, 
which would add to its importance, and help to defray 
expenses. Examination fees in like manner. Evening 
classes for adults could be managed under somewhat 
similar conditions. 
THE INFLUENCE OF AQUEOUS VAPOUR ON 
METEOROLOGY 
HE remarks on Meteorology contained in your summary of the 
scientific advances during the last year, encourage me to offer 
a few observations on the subject. Where so little is deter- 
mined, speculations even by unknown contributors may receive 
some consideration. I shall begin with the subject of aqueous 
vapour, to which, I think, too much importance has in some 
respects been attached as a meteorological agent. 
I shall commence by offering a determination of the specific 
heat of aqueous vapour at constant volume, which has not, to my 
knowledge, been hitherto given. It is evident that if a given 
weight of water be evaporated at o° C., and then raised to 100° 
C., without change of volume, the total heat absorbed by it is 
the same as if it had been raised to 100° C. in the condition of 
water, and then evaporated so as to fill the same volume. Now 
if this amount be one kilogramme, and ¢ be the specific heat of 
vapour at constant volume, the total heat absorbed in the first 
case is (adopting Regnault’s formula for latent heat—yviz., 
L = 606°'5 ~ 0°695 #)— 
606°°5 + 100¢. 
And in the second case the equivalent amount is 
537° + 100°8 = 637°8, 
the total amount of heat required to raise one kilo. of water from 
0° to 100° C. being 100°8, according to the best determinations. 
From this equation we obtain for the mean value of c be- 
tween 0° C. and 100° C, 
c = 0°313 
But the specific heat of aqueous vapour at constant pressure seems 
to be about 0°475. Hence for each kilo. of aqueous vapour raised 
through 1° C. at constant pressure, we have 0°313 heat units 
expended on internal work, and 0°162 on external work. The 
proportion is 1:0°517. In dry air the proportion in question, 
according to the latest determinations, seems to be I : 0°421. If 
the same amount of heat therefore be applied to produce expan- 
sion in vapour and in dry air, it produces a greater expansion in 
the former case. But the difference is not very material. In 
round numbers 30 per cent. of the absorbed heat is employed in 
producing expansion in one case, and 35 per cent. in the other. 
Apart from the different absorptive powers of air and vapour, 
this difference would be hardly perceptible. For equal quanti- 
ties, heat absorbed by vapour has little (if any) greater effect in 
producing air currents or barometric depressions than heat ab- 
sorbed by air. If the heat is absorbed in producing evaporation, 
the effect is still less. It is well known that less than one-eighth 
of the heat so absorbed goes to produce external work—a much 
smaller proportion than if it had been absorbed by dry air. 
I may observe that the result here arrived at for aqueous 
vapour supposes that its co-efficient of expansion between oF G: 
and 100° C, is greater than that for air in the proportion of nearly 
7to6. This would make the mean co-efficient about 0°00427 
for 1° C. between these limits. 
The next thing to ascertain is the quantity of aqueous vapour 
suspended in the air at any given time. This, of course, cannot 
be ascertained exactly, but it seems to me to be wholly erroneous 
to measure it by the tension of vapour at the earth’s surface re- 
latively to the pressure of dry air. It is generally supposed 
that the upper strata of the atmosphere are relatively drier than 
the lower ; but even if we suppose them to have an equal rela- 
tive humidity, the actual yapour-tension will become less in pro- 
portion to the tension of dry air at every step of the ascent. 
According to Sir J. Herschel, the law by which the temperature 
varies with the pressure of the air at any elevation is given (in 
Fahrenheit degrees) by the law 
t= -87° + 9'0667 p - 013332" 
