. An encyclopædia of gardening; . ndicators of weather differ from those in commonuse only in two instances, that of the registering thermometer and regu-lating thermometer. The barometer, hygrometer, rain-gauge, and vaneor Eolian index, may all be usefully employed in gardening, (1278.)and should be fitted up in and about the gardeners office. The rain-gauge and vane may be placed on the roof of his office, and shouldcommunicate with the interior by means of tubes and machinery, thedetail of which is perfectly known to opticians, and such as fit up ap-paratus of this kind. 1488. Sixs register
. An encyclopædia of gardening; . ndicators of weather differ from those in commonuse only in two instances, that of the registering thermometer and regu-lating thermometer. The barometer, hygrometer, rain-gauge, and vaneor Eolian index, may all be usefully employed in gardening, (1278.)and should be fitted up in and about the gardeners office. The rain-gauge and vane may be placed on the roof of his office, and shouldcommunicate with the interior by means of tubes and machinery, thedetail of which is perfectly known to opticians, and such as fit up ap-paratus of this kind. 1488. Sixs registering thermometer (Jig. 216.) is so contrived as toindicate the extreme points to which it falls or rises in the course ofthe day or night, and is, therefore, particularly useful as a check uponthe working gardeners, who have to attend to the fires, or steam, &c. ofhot-houses in the winter time. In the open air it is also a very usefulinstrument, by pointing out the extremes of temperature. ( art. Thermometer.) 216. 50^ SCIENCE OF GARDENING. Part II. 1469. Kewleys alarum-thermometer {Jig. 2190 consists of a glass tube (a, a), about teninches in length, hermetically sealed atone end, and united at the other to a capillary tube(6, b), with an intervening and also a terminating ball (c and d). Imagine this double tubeplaced in a horizontal position, the largest tube, and half the intervening ball, filled withspirits of wine ; and the smaller tube and half of both of the balls, with mercury. If thetube is now fixed by its centre in a brass frame (e), and nicely balanced, it is evident thatevery change in the temperature of the atmosphere will produce a change in the positionof the centre of gravity of the tubes. One degree of heat, by expanding the spirit, willpress on the mercury in the intervening ball (c), and drive part of it over to the termi-nating tube (rf), which end will, in consequence, descend like the beam of a pair of scalesor of a steam-engine. Hence a mov
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Keywords: ., bookcentury1800, bookdecade18, booksubjectgardening, bookyear1826
