234 J'^urnal oj AgnciilUirc. Victoria. [lo April, 19] i 



Australian cigar leaf wdth good results, and have built rooms in which tem- 

 peratures and humidity can be regulated. Should, however, any growers- 

 wish to experiment, it is well to advise them that a temperature of 120. 

 deg. is as high as it is safe to allow tobacco to go, though in rare cases 

 130 deg. has been used. If this is exceeded the life in the leaf is killed 

 and the enzyme which performs the work desired is destroyed ; consequently,, 

 the leaf is not changed. It must be borne in mind that the whole process- 

 is partly a life and partly a chemical one, so too much care in observing 

 the necessary conditions cannot be taken. 



Experiments have been carried out by the Department of Agriculture 

 in inoculation with pure cultures of ferments from Havana grown leaf. 

 Though the tobacco so treated turned out well, further experiments will be- 

 necessary before it can be detinitely stated that the success was due solely 

 to inoculation. 



(7'(? be continued .) 



RAIN TREES. 



Alfred ]. Eii'art. D.Sc., Ph.D., F.L.S., Goverinnoit Botanist of Victoria- 

 and Professor of Botany and Plant Physiology in the Melbourne 

 University. 



It is a very common superstition that particular trees have a special 

 power of producing, manufacturing or condensing rain, and one of the- 

 trees with which this superstition is most closely connected is the so-called 

 "Rain Tree or Guango " of Mexico and Peru (Albizsia Saman, F.v.M. 

 {Pithecolobium Saman, Benth.). For instance, a correspondent recently.- 

 forwarded a newspaper cutting on the Rain Tree of Peru, containing the 

 following statements : — 



Plantations of the Rain Tree of Peru, the '' tamarcaspi," are claimed to offer 

 great possibilities as irrigation works. The tree grows readily in any soils, reach- 

 ing a large size, and has a luxuriant foliage, with a remarkable power of collect- 

 ing and condensing atmospheric moisture. Its capacity, moreover, is increased by 

 the usual heat of a drought. The water falls from the leaves and oozes from the 

 trunk, and forms veritable rivers, w'hich can be led as irrigating canals to any 

 point desired. A single tree is estimated to average nine gallons of rain a day. 

 Making liberal allowance for evaporation and infiltration, a square mile grove of 

 the trees would supply for distribution about 100,000 gallons of water daily. 



Needless to say, such statements are quite ridiculous. No trees have- 

 the power of condensing or manufacturing rain. The roots of many trees 

 contain stored water. The stems of others, when cut across, may bleed 

 freely and the leaves of grasses and other plants often show, particularly 

 in the early morning, adhering drops of water, which are not dew drops- 

 but which are actually exuded by the plant. In all such cases, however, 

 the water in question is absorbed from the soil by the roots of the plant, 

 and if the .soil is dry the plant will soon die from lack of water. The 

 " dew drops " on grass leaves are natural.ly most common when the air 

 is moist, but this is simply because the roots continue to absorb water ; 

 but the leaves, being in moist air, lose little or none, and the excess water 

 is exuded from the leaves in liquid form. As soon as the air becomes dry, 

 and the leaves are transpiring actively, the exuded drops of water dry up 

 and disappear. This statement is not to be taken as a denial of the fact 

 that dew may form on leaves if they happen to be in moist air and are 

 colder than the surrounding atmosphere. But such dew rarely forms large 



