The second burnout, which was controlled by the liquid microlayer and dry area on the heating surface, was analyzed theoretically on the basis of bubble characteristics upon the electro-conducting glass submerged in stagnant water under the atmospheric pressure, and it was found that by suppressing the hydrodynamic instability the burnout heat flux could be increased considerably, but it encountered second limitation which could not be overcome by any ordinary method. The numerical value of the second burnout for water heated on horizontal surface under the atmospheric pressure was estimated to be about 10⁷kcal/m²hr which was almost ten times as large as the usual value. Discussion was also made on the transition boiling, and it was concluded that the so-called transition boiling with considerable superheat was really a film boiling because of no liquid film upon the heating surface.