1902 Tyco's 1300A Lloyd's Hygrodeik (Early Model)

A very early, rare, and functional Tyco's Lloyd's Hydrodeik. Dated 1902, this hygrometer uses a wet bulb thermometer (left) and dry bulb thermometer (right), with an adjustable pointer to read relative humidity and dew point temperatures via engraved nickel-silver plate. The body is comprised of an olive-painted brass. US-Made, Manufactured Rochester, NY. 

In the early days of meteorology, scientists or learned professionals would use these readings, coupled with a barometer, to accurately predict the weather. Moreover, the same scientific principles were applied to sensitive indoor environments (from eradicating mold to preservation purposes to ensuring the accuracy of precision instrument readings).

 Directions for Use:

 "To find the relative humidity, swing the index hand to the scale at the left of the chart and set the sliding pointer at degree line upon the chart which corresponds to the temperature shown upon the wet-bulb thermometer. Then swing the index hand to the right until the sliding pointer intersects the curved line which extends downward to the left from the degree line upon the chart corresponding to the indicated temperature of the dry-bulb thermometer. At this intersection the index hand will point to the relative humidity on the scale at the bottom of the chart."

Source: 1919 Tyco's Industrial Equipment Catalog (page 74)

Plate Marked:  LLOYD'S HYGRODEIK / TYCO'S / ROCHESTER, N.Y. / USA / COPYRIGHT 1902 BY ANDREW J. LLOYD & CO., BOSTON

(Dew point, relative humidity, wet bulb, dry bulb, low electrical tension, and high electrical tension are also distinguished on the engraved plate)

Similar Model Featured at The University of St. Andrews.

Later models utilized by the US Weather Bureau as stated in the 1930 Welch Catalogue. 

Weight: 2 lbs. 5.6 oz.

Dimensions: 8.00" x 3.25" x 10.00"