An Agricultural Experiment Station.



corn into the air. They receive it, as it falls, and nose it about not altogether approvingly. The call was for salt,- what a misappropriation of the shepherd's signal!
      The habitat of the meteorological department of the station stands revealed to the most unobservant. The gilt arrow and the revolving cups are as unmistakable as the sign of the Boar's Head or the Bunch of Grapes. They shine and turn in the midst of cylinders, drums, and the whatnot of meteorological equipment, on the top of a tower at the corner of a great dormitory. The room is small, and the roof above it is a mere platform.
      The astronomer and the meteorologist divide the heavens between them. The cross of the equator and the ecliptic, the restless golden fleets which never come to port, distances so vast and relations so complex that the brain is giddy before them, the enticing harmonies of light, color, and form render the chart of the astronomer an illuminated page.
      "Morning red," —as ominous as a hectic flush,— the manifestations of rain, fog, and dew, the varying pulse of the wind and temperatures systematically taken,- from data such as these the observatory derives the precautionary measures which it urges.
      The recording room contains the solution of these puzzles. The first instrument encountered is simple enough. It hangs in a sheltered place outside the north window, and consists of two thermometers. One with a dry bulb is for taking the temperature of the air; the other with a bulb kept wet by a covering of muslin attached to a wick dipping in a cup of water denotes the evaporation. The meteorologist fans them vigorously, since the wind, the natural ventilator, is not at hand to perform this office, and writes their readings in a book. There is a table for computing the dew-point from the difference between these readings. Lieut. Greely's rule is as follows:—
      "The difference between the readings of the thermometers multiplied by 2.5 and subtracted from the reading of the dry thermometer gives the approximate degree to which the temperature of the air will fall the coming night unless there is a change of wind to a moist quarter or increase of cloudiness intervenes. If the mercury falls below 32° there will be frost; above 36° there is little danger."
      This psychrometer, as it is called, is the only one of the instruments not self-registering. The others are ticking solemnly away in their places, mute, patient scribes, with pen forever at the paper which forever slides away without an error.
      There are three wind instruments. This same anemometer of the revolving cups, the anemoscope, whose connection with Eurus and Notus and their wild company is by the gilt arrow or vane, and a nameless instrument for measuring the force of the wind. The four upper cups of the anemometer are set on the ends of a horizontal cross supported by a vertical shaft running up several feet above the roof. They turn with a speed one third the velocity of the wind. To the lower end of the shaft revolving with the cups is attached an endless screw connected with wheels which move a cam. One turn of the cam is equivalent to twenty miles of wind. It also brings the recording pen from the bottom to the top of the chart; thus the number of times the pen crosses this space multiplied by twenty gives the number

Nepper Plant House and the Insectary

Left: Nepper Plant House, North End. Center: Nepper Plant House, South End. Right: Insectary.

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