SCIENCE AND INDUSTRY. 
occupied and the costly cumbrousness of the plant, to which must be 
added the great variability in the rates of power production. In short, 
the system seems to present in an exaggerated form all the drawbacks 
attaching to wind-power. 
Ruskin, in one of those works which are at once a delight to the 
lover of literature and the despair of the seeker for ideas, reproved his 
generation for preferring steam-power to air-power since the latter, he 
observed, cost nothing. Such fallacies constitute, of course, much of the 
stock-in-trade of all superficial writers, but commonly find a happy 
‘oblivion in the corner of a country newspaper or in the pages of a 
popular magazine. They do no harm save when as in Ruskin’s case the 
sterility of the “half-idea” is to some degree concealed by the perfection 
of the phraseology in which it is embodied. It was his contemporary 
who pronounced the bulk of his generation to be “mostly fools,” and, 
though Ruskin was less direct in his methods, he evidently thought 
that the preference for steam of the great creative intellects of the past 
century was to be attributed to innate imbecility or sheer perversity. 
His suggestion, however, merely illustrated once more the every-day 
fact that the man who writes easily will not often be bothered to 
cull the results of the past experience of mankind, but, like the pro- 
verbial German anatomist, prefers the, to him, easier task of construct- 
ing his “camel” out of his inner consciousness. 
Wind-power is, of course, cheap only in exceptional circumstances, 
where the total amount of power required is insignificant, and intermit- 
teney of working is immaterial. A windmill 40 feet in diameter is 
rated at about 8 horse-power, and costs about £400, or about £50 per 
horse-power. It cannot be relied on to work for more than one-third 
the total number. of hours in the year, and, even so, the working hours 
are distrjbuted erratically. 
In this latter regard a sun-power plant would, in a favorable 
climate, probably be somewhat less capricious, but the windmill, cum- 
brous and bulky though it may be in comparison with its effective out- 
put, is still many degrees superior in this regard to the best sun-power 
plant yet constructed. 
In the plant erected at Meadi, and described in Mr. Ackermann’s 
paper, the steam-generators comprised a series of eléments, each con- 
sisting of a cast iron boiler 34 inches wide by 14% inches deep and 205 
feet long. This boiler was arranged at the centre of a parabolic mirror 
of the length stated, and measuring rather over 14 feet in extreme 
width. Of these huge mirrors there were five, and the reflecting portion 
consisted of flat plates of silvered glass arranged round a parabolic 
surface. These enormous mirrors were mounted on rollers, as it was 
necessary to make them “follow the sun” in its passage across the sky - 
from east to west. The plant was found to work best with a steam 
pressure of about 63 Ib. gauge. The engine was of a very special 
- design, having small clearances and very large exhaust ports, the latter 
being provided in order to take better advantage of high vacua than is 
practicable with the normal type of reciprocating engine. In some 
preliminary trials, some excellent results have been recorded with 
engines of this type, an efficiency ratio of as much as 52.7 per cent. 
being obtained, which is certainly a remarkable figure for an engine 
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