Choice of what grade of water to use in a HHO generator: Rainwater, spring water and tap water all contain impurities. A typical analysis will show minerals, suspended solids and other contaminates contained in these varieties. These impurities will precipitate out of the water when subjected to electrolysis.
white race: people of european decent are all grouped together for simplicity(even though we all know of each others variations and tribes), includes skin types of thin brown, to yellow to very white(eye color and hair color has no significance).
For other uses, see Ethnic groups in Europe. The Caucasian race (also Caucasoid or occasionally Europid) is a taxon historically used to describe the physical or biological type of some or all of the populations of Europe, North Africa, the Horn of Africa, Western Asia, Central Asia, and South Asia.