additional proof that something that was believed (some fact or hypothesis or theory) is correct

additional proof that something that was believed (some fact or hypothesis or theory) is correct

additional proof that something that was believed (some fact or hypothesis or theory) is correct

additional proof that something that was believed (some fact or hypothesis or theory) is correct

additional proof that something that was believed (some fact or hypothesis or theory) is correct

additional proof that something that was believed (some fact or hypothesis or theory) is correct

additional proof that something that was believed (some fact or hypothesis or theory) is correct

additional proof that something that was believed (some fact or hypothesis or theory) is correct

a colorless flammable gas used chiefly in welding and in organic synthesis

a colorless flammable gas used chiefly in welding and in organic synthesis