In some technical gas burners the gas stream is subdivided in a number of single jets which will be influenced mutual. The paper shows some results of experiments with very simple town gas and natural gas burners with three and five parallel single jets. Measurements of concentration, flame length, and flame width in free and enclosed multiple flames are described. The results show that there is a simple relation between the flame length of multiple burners and the number of jets and the distances between the central and the outer flames. The data of flame length derived from photography and from the axial concentration of CO agree well; so it is possible to measure the length, the width, and the average value of combustion intensity of flames quickly and with fairly good accuracy.