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.
Most people begin to show symptoms of HIV within two to four weeks of exposure. Recurrent or persistent fevers may be one of the first symptoms you experience after contracting HIV. In acute HIV, a fever also may be accompanied by: 1  sore throat. 2  rash. 3  fatigue. 4  swollen lymph nodes. 5  other virus-like symptoms.