684 CURRENT TOPICS. [J. F. I.

Gas Cultivated Tomatoes.-(Gas World, Vol. CIII, No. 2663.) In a glass house IOO ft. by 30 ft. at Peakhurst, near Sydney, MR. C. DEVINE is pioneering a new development in the tomato-growing industry, at least in Australia. Using varieties of tomatoes from the Channel Islands, New Zealand and the United States, he expects, with the aid of a gas heating installation to garner IO lb. of fruit from each of 1,000 plants at the end of October, just when it will be almost impossible to secure a tomato in Sydney. The heating plant installed consists of two units, thermostatically controlled at opposite ends of the house. The soil is heavily fertilized with 18 loads of manure, half a bag of superphosphate and a half a bag of bone dust. This is the first adaption of gas for heating in this way in the southern hemisphere.

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Electric Anemometer For Air Conditioning.-(Elec. World, Vol. 105, No. 18.) To measure air stream velocities W. V. HUKILL of the Bureau of Agricultural Engineering has devised a simple apparatus probably useful for air currents in any direction. It consists of a thermocouple, both junctions of which are exposed to the air stream. One junction is heated by current from two dry cells. The e.m.f. of the couple is a measure of the temperature difference and the faster the rate of air movement the less the temperature difference. Current value is measured by potentiome- ter and adjusted to the desired value by rheostat. The resulting thermocouple e.m.f. is converted directly to air velocities in feet per minute. The instrument has been used successfully in studying horizontal air movement in refrigerator cars where velocities range from I0 to 100 ft. per minute.

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A New Method of Water Heating.-(American Gas Journal, Vol. 143, No. 3.) In an attempt to reach the market for a domestic gas water heater of low first cost and a minimum operating cost the Handley Brown Co. of Jackson, Mich. has developed a new heater that transfers the heat to the water by reflection. Its trade name is Mirro-Shell. The utilization of this principle in proper design makes in a few minutes an efficient automatic storage gas water heater out of a range boiler regardless of the type of fuel previously used to heat the water. Highly polished, non-tarnishable metal mirrors are placed around the range boiler so as to reflect through its sides the heat generated by a small gas flame at the base of the tank. A surprisingly high over-all operating efficiency is obtained.