Laminar pool flames of four straight-chain alcohols were studied in uncooled glass and copper burners and water-cooled glass burners. The mass burning rate ri, increased with the burner diameter d decreasing as ri, 0: 6", where n e 1.2 for uncooled glass burners. The values of ni in copper burners were lower by a factor of 1.5-2 than those in glass burners of the same diameter. Vigorous boiling of the subsurface layer of liquid occurred in sufficiently narrow uncooled glass burners, and numerous burning droplets were observed to traverse the flame. The quenching diameter d, was measured. For uncooled copper burners d, increased with increasing molecular weight Mr of the alcohol, from a2 mm for propanol to ~20 mm for decanol. For uncooled glass burners d, was much lower (l-2 mm) and less dependent on molecular weight. The product of d, and the critical mass burning rate is assumed to have a characteristic value for the stability of diffusion burning, in accordance with the Zel'dovich criterion (Pe) = (Pe), = const. for flame stability in gas mixtures. However, the stability of diffusion burning increased with increasing heat losses from the burner wall. Two possible interpretations of this paradoxical effect are suggested. Pool flames were studied by Blinov and Khudyakov'. More recently other papers*-' were published. Dependence of burning rate (linear u or mass ti) on the burner diameter d, on the chemical nature of the fuel, and on the oxygen concentration in the ambient atmosphere was investigated. However, burning data for small values of d are scarce, and no values for quenching diameter are available from the literature. The aim of this work was to study the ti(d) dependence more closely (especially at small values of d) and to determine the quenching diameter for pool flames. Uncooled glass and copper burners and water-cooled glass burners were used. l 1 mPas=l cP