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.
These are the three stages of HIV infection: Within 2-4 weeks after HIV infection, many, but not all, people develop flu-like symptoms, often described as âthe worst flu ever.â Symptoms can include fever, swollen glands, sore throat, rash, muscle and joint aches and pains, and headache.