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.
Signs and Symptoms. Many people don't have any symptoms when they first become infected with HIV. Some have a flu-like illness, called HIV sero-conversion syndrome, a month or two after exposure to the virus. This illness may cause a variety of symptoms, including: 1  Diarrhea. 2  Enlarged liver or spleen. 3  Fever. 4  Enlarged or swollen lymph nodes. 5  Headache. 6  Muscle pain. 7  Nausea and vomiting.