FoL. XII. No. 269. 



THE AGRICULTUR.'iL NEWS.- 



175 



In the fifth section of tlie paper, dealing with the length 

 •of period of coagulation, it is reooinmeuded that latex should 

 be coagulated slowly by using only a slight excess beyond 

 the minimum amount of acetic acid necessary, and a .5-per 

 cent, solution of the acid. The resulting rubber should be 

 left overnight and passed through the machines on the follow- 

 ing day. 



Of the substances which inhibit coagulation, dealt with 

 lin the succeeding section, sodium and potassium hydroxide 

 were found to have a marked inhibiting effect, whilst both 

 barium and calcium hydroxide solutions had a peculiar 

 agglutinating effect on Hevea latex; the latex thickened to 

 jA marked extent, but no cohesion of the particles occurred, 

 that is, no real coagulation took place. The general conclu- 

 sion is reached, that latex solutions behave in the same way 

 as other emulsions or colloid solutions, and that the action 

 •of the coagulant on the caoutchouc globules or particles, 

 does not need the assumption of any preliminary action on 

 the proteid matter by which the rubber globules are subse- 

 quently entangled or precipitated. 



Interesting results accrued from the next investigation 

 on the effect of iron salts on raw rubber It was demon- 

 strated that absolute cleanliness should be preserved when 

 metallic cups are used in collecting, because iron salts not 

 ■only darken the rubber, but also cause it to become soft 

 and tacky. Since perfect cleanliness is almost impossible, 

 glazed earthenware, porcelain or glass cups should be 

 substituted for those made of iron. The rollers of all 

 washing machines should also be kept free from rust. 



As regards the effect of common salt on rubber, dealt 

 with in the eighth section, it was shown tlxat the presence of 

 this compound, because of its hygroscopic property, checked 

 drying, and incidentally induced the attacks of fungi and 

 bacteria from the air. In connexion with tlie effect of using 

 peaty water in collecting, and for washing — frequently 

 necessitated in outlying districts of low elevation— it was 

 iound that for washing it was not unsuitable, but its 

 employment in the collecting cups resulted in an undesirable 

 darkening effect. Treatment of such water with small 

 quantities of lime was found to eliminate this effect. 



In the succeeding section, the effect of sunlight on 

 rubber is dealt with. Experiments in this direction showed 

 that samples exposed to the suns rays became tacky, the 

 tackiness increasing with the length of exposure. Samples 

 of 'crepe' appeared to become tacky more rapidly than sheet, 

 owing, probably, to the greater amount of surface exposed. 

 Another observation proved that the tackiness was due to 

 exposure, for when the rubber samples were protected by the 

 wooden bars of the window in which they were suspended, 

 the surface of these places was quite free from tackiness. 

 The ability of copper salts to induce tackiness is 

 ■demonstrated in the next section, and it was found that, 

 so far as these experiments went, tackiness on rubber samp- 

 les could not be traced to the use of copper rollers in the 

 Malayan washing machines. 



The subject will be continued in the next issue of the 

 A'jricxUUirnl -\'e«.5. 



FORESTRY IN HAWAII 



The following summary of 

 valuable recommendations is taken 

 of the Board of Commissioners ol 

 -Forestry of Hawaii, for 1910-12: — 



interesting and 

 from the Report 

 Agriculture and 



From the statements in the foregoing pages ("f the 

 report) it should be evident that at the present stage of the 

 game in Hawaii the essential need in forestry is for the better 

 production of the native forests. And this is required not 

 because of the worthiness of the forest in itself to be. cared for, 

 but because on the forest depends the continuance of an 

 assured water supply. There are other needs, too^ for there is 

 much forest work in Hawaii that requires urgently to be done, 

 to say nothing of tree planting on waste lands tb:'.t 'vill 

 unquestionably be of profit to those who undertake it. But 

 first and foremost at this time comes the call for better care 

 of the existing forests on the water.sheds. The necessary steps 

 to be taken are fencing and the eradication of wild stock :n 

 the forest reserves — cattle, goats and pigs — which should be 

 followed by the extension of the forest, through [ilanting, 

 where the cover has been broken from any cause. 



To carry out as it should be done, the.se extensions of 

 forest work will necessarily require larger expenditures than 

 have been made in the past. To meet this demand 

 a portion of the revenues now derived by the Territorial 

 Government from water licenses on streams in the forests 

 should be devoted to forest work In a word, some of the 

 money derived in these islands from water, a product of the 

 forest, should be re-invested in the forest, to the end that 

 for the future the supply of water may be assured, if indeed 

 it cannot be increased. A revolving fund so established 

 will, in the end, pay itself back many fold. It is the 

 experience of all countries where forestry is practiced that 

 the re-investment, up to a certain point, in forest adminis- 

 tration of the revenue derived from the forest, leads to an 

 increase in subsequent returns. Hawaii would be no exi;ep- 

 tion to this general law. Provision should be made forgetting 

 the ade<|uate protection of the forest started without more 

 delay. This is a matter that should be brought in the most 

 forcible way possible to the attention of the Legislature. 



Along with the adequate protection of the native forest, 

 the activities of the Division of Forestry should be carried 

 on in accordance with the general programme that has been 

 in force for the past several years. The growing and 

 distributing of seedling trees, free or at cost price, from the 

 Government Nursery at Honolulu and from sub stations on 

 the other islands; the extension of this work through the 

 establishment of additional sub nurseries in other districts;' 

 the continuation of the policy of furnishing advice and 

 suggestions as to tree planting and other forest work; and 

 the prosecution, for a while longer, of the campaign of 

 education as to the necessity and desirability of forest work, 

 until a larger proportion of the owners of fee simple land 

 that should be under forest cover, take effective steps to 

 make it so; these are all lines of activity that should be 

 continued, that could to the advantage of the people of the 

 Territory, very well be expanded. 



In addition, tree planting by private corporations should 

 be further encouraged, both as to the planting of stands of 

 commercially valuable trees for fuel, posts, etc., on w<tste 

 areas near plantation camps, and also as to spreading the 

 Algaroba forests along the sea coasts of the several island.s. 



The forest fire danger in Hawaii is fortunately not 

 great in most districts, but for this very reason all the more 

 care should be taken to keep fire out of the forest altogether. 

 New comers to Hawaii have ditliculty in appreciating how 

 inflammable much of the vegetation is, even in the true wet 

 forests. With the increasing necessity for keeping our water 

 sheds in the best possible condition it is essential that na 

 chances be taken with fire. 



