The average heat transfer rates of gravitational and magnetic convection of water heated from below and cooled from above are measured for two cases of cold wall temperature theta(c) at 10 degrees C and 30 degrees C. The height of the cylindrical enclosure is 2 mm with 40 mm in diameter. The magnetic field is imposed in a vertical direction to increase or decrease 29% of the gravitational acceleration in a bore space of a super-conducting magnet of 10 T at the solenoid center. The group of data at theta(c) = 30 degrees C gives a better agreement with the classical heat transfer rate of Silveston than that at theta(c) = 10 degrees C. This is probably due to the almost constant value in the volumetric magnetic susceptibility of water at about 10 degrees C. (c) 2006 Elsevier Ltd. All rights reserved.