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.
What are the symptoms of HIV and when do they appear? Most people who are infected with HIV experience a short, flu-like illness that occurs between two and six weeks after infection. After this, HIV often causes no symptoms for several years. It's estimated that up to 80% of people who are infected with HIV experience this flu-like illness. The most common symptoms are: fever (raised temperature) sore throat. body rash.