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.
The rash can be just a heat rash or psoriasis or other types of skin infection. There are several others signs and symptoms to identify HIV infection. Some of them are loss of appetite, weakened immunity, and diarrhea, loss of memory, poor concentration, sudden weight loss and joint pain.