The latest phytotron unit at Davis (a rotating sunlit room that follows the sun) is now in operation, and is expected to be particularly useful for plant growth experiments which benefit from intense sunlight. This 20 × 20 ft room has a roof and front face of double-pane and clear plastic panels with prismatic lower surfaces to direct sunlight downward from the roof. Photocells which trigger an electric motor cause the room to face the sun continuously, receiving strong direct sunlight from dawn to sunset.

Excellent cooperation and assistance were received from the Departments of Agricultural Engineering and Plant Service, and the Capital Machine and Welding Works, Sacramento. The Rohm and Haas Co. donated many of the plastic sheets in the roof.