370 
POPULAR SCIENCE REVIEW, 
The direct pressure upon one foot square of steel plate, with 
the blast acting at right angles to the plate, was 3*24 lbs., which, 
according to House and Smeaton’s tables, evidences a wind 
velocity of about twenty-five miles an hour. The same plate in- 
clined at an angle of 15° from the horizontal, received a direct 
pressure of only 0*33 lbs., accompanied by a lifting pressure of 
1*5 lb. There were various inclinations and different areas tried, 
but there is no need here to go fully into the tabulated results. 
It will be sufficient to say that a plane of one square foot, 
impelled at an angle of 15° against air moving at the rate of 
about twenty-five miles an hour, will support a weight of one 
pound and a half, whilst it will only meet with a resistance to 
its forward motion of five ounces and a quarter, although of 
course there would have to be added to this the resistance due 
to the form in which the weight is disposed. A less angle than 
15° could not be tried owing to some obstruction in the 
action of the instrument, but the experiment shows very great lift- 
ing force in proportion to the power which requires to be expended 
in the propulsion of the plane. It shows also that the ratio of 
the lift to the thrust greatly increases as the inclination dimin- 
ishes, whilst the force to propel is equally lessened, and thus the 
sustained flight of birds, often with motionless wings, is in great 
part accounted for. There exists also another circumstance 
which is favourable to the extension of the sustaining surface, 
viz. that the lifting power relative to the square foot increases 
in some yet unknown ratio with the extent of surface exposed, 
upon the principle which has been ascertained that the more 
the total area of a ship’s sails is cut up into portions, the less the 
effect. 
Such fundamental experiments accord with the legitimate 
duty of the society to which I have the honour and pleasure 
to act as honorary secretary. It is left to the spontaneous 
efforts of individual members to work up to the data thus 
established. 
Upon such men, whilst the world generally look with 
amused pity, the eyes of a cautious and watchful few are 
fixed, ready to take advantage of the first hopeful result. It 
is my earnest hope that the society will stand between such 
men and injustice at the time of the general scramble for 
pecuniary recompense. 
It will be the place here to allude to the late and very 
expensive attempt of Mr. Thomas Moy to construct an appa- 
ratus by means of which, in his trials in order to obtain a ful- 
crum upon the air, he practically tested the correctness of the 
facts brought out and tabulated. 
Mr. Moy was an exhibitor at the Exhibition of the Society 
at the Crystal Palace in the year 1868. For some purpose or 
