[en] A method for measuring the parameters of a plasma blob is described; it involves recording the flight path length and the interaction of the blob with probing light rays. For improving the accuracy of the measurements, the time of flight of a blob of one path length is compared with the time taken by light for passage through the optical path length; one of these lengths is varied until both times coincide within the limits of the length of time of the blob and the results of the measurements of the flight path length and the optical length of the path of light are used for estimating the length and velocity of the blob. The method described can be used in plasma and electron-blob diagnostics. (author)