... constructed; to the second we are indebted for the power of the lenses, and the blessings of sight, for the light acts upon the retina of the eye in the samemanner as on the lens of a camera. The latter ... the cross bar g, and fits the pot so accurately that iteffectually prevents the escape of the vapor of the iodine, bromine or other accelerating liquid containedtherein. The other half of the ... [hipho_18.gif] The evaporation of the water from this bulb decreases the temperature of the mercury in the tube b in proportion to the dryness of the atmosphere, and the number of degrees the tube...