1 In the mercury barometer, atmospheric pressure balances a column of mercury, the height of which can be precisely measured. 2  Of the many different varieties of mercury barometers, most variations arise from different techniques for measuring the height of the mercury column.
Recognizing the Symptoms of an HIV Rash. 1  1. Check for a rash that is red, slightly raised, and very itchy. 2  2. Note if the rash appears on your shoulders, chest, face, upper body, and hands. 3  3. Pay attention to other symptoms that may occur when you have HIV rash.  4. Be aware of the causes of HIV rash.
HIV rash Symptoms. The dermatologic problem most often appears 2-3 weeks after being infected with the virus. The rashes can occur on any part of body, but usually affects the face, chest, back, hands, legs and trunk. Additionally, men infected with HIV can develop sores and fluid-filled blisters on the mouth, genitals and eyes.