The phase-front distortion of laser radiation propagating through the turbulent atmosphere has been measured simultaneously at several wavelengths in the visible using a long-range Mach-Zehnder interferometer with high spatial and temporal resolution (476 nm

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A density increase of He II up to Ap/p= 3 9 10 .4 due to turbulent flow caused by a heat current in a wide tube has been observed by pycnometric measurements and by measuring the dielectric constant of He II. The state of increased density appears to be metastable against mechanical disturbances.