163 

 UTILIZATION OF SUN POWER. 



An interesting- paper was read at the International Congress 

 of Tropical Agriculture on the utilization of sun power for irri- 

 gation and other purposes connected with agriculture in the 

 tropics. The principle involved in these machines is the con- 

 centration of radiant energy by means of mirrors on to boilers 

 enclosed in glass cases to check radiation. 



Mr. F. Shuman stated that results of tests of the sun power 

 plant near Cairo in Egypt had been satisfactory. It is estimated 

 that (power can be produced in the tropics at the same cost as if 

 coal were less than 10s. per ton ; and as coal in many parts of 

 the tropics costs £2 10s. per ton, upwards, the saving to be 

 effected by means of sun power plants is quite obvious. Though 

 sun power plants cost more than coal-burning plants, the saving 

 effected by not requiring any fuel is sufficient to wipe out the 

 extra capital cost after two years, and in four years to pay en- 

 tirely for the whole equipment. 



Discontinuity in sunlight is overcome bv the art of using low 

 pressure steam : boiling water is stored in tanks and the steam 

 drawn upon as required. — Agricultural Nexvs. 



DROPPING OF BREADFRUIT. 



We often have callers and letters asking why the young fruit 

 drops from certain breadfruit (or other fruit) trees, so that none 

 mature. This is usually because there is too much vegetative 

 vigor in the trees — they run to leaf and twig, and this condition 

 is usually caused by a too plentiful supply of water at the wrong 

 time. 



As a rule such trees are standing in yards where there is a 

 water pipe, and the water is constantly soaking the roots, induc- 

 ing fresh growth. When once the breadfruit tree blossoms free- 

 ly, the water should only be allowed moderately when the soil is 

 seen getting dry; and the fruit will thus hold. 



Where the conditions of growth are not governed by a water 

 pipe, and the fruit will not hold, the owner should try, as an ex- 

 periment, girdling the tree with a wire drawn tight round the 

 trunk, doing this just when the fruit is setting. It will generally 

 be found that this will prevent the falling of the fruit. When 

 the fruit is over half fit the wire can be taken off and the bark 

 will heal over in three months. 



This can be done with all fruit trees that drop their fruit just 

 after setting, or when trees make plenty of leaf growth but do 

 not fruit at all. Of course, dropping of fruit is not to be con- 

 founded with young fruits dropping because of the trees bearing 



