Vol. X. No. 241. 



THE AGRICULTURAL NEWS 



•229 



The following circumstances aru mentioned in order to 

 indicate the superiority of this method for pruning vanilla, 

 namely, that by the simple process of pinching back and 

 crooking the vine, those parts which are responsible for frait- 

 bearing are kept immediately in the course of the chief 

 direction of the flow of the sap: their suppression after each 

 picking does not change this arrangement in any way, so that 

 it is alwaj's by means of a mother-branch which has never 

 borne fruit that the sap circulates and reaches the different 

 organs: and that it is always on new branches which have 

 not yet fruited that the fructification of each year appears. 

 It is claimed that the adoption of this method brings about 

 a more regular and abundant production of pods and even 

 a longer life for the plant itself. 



material which remains floating is then placed in a compressor 

 with water and subjected to a pressure of 2.50 lb , with the 

 result that the cork bagasse is waterlogged. The result of 

 this operation is the practically comi)lete separation of the 

 rubber from bagasse. The practically clean rubber is then 

 further cleaned by being passed through a beater-washer. 

 This is merely an iron tank, with an undershot paddle-wheel 

 with a great many blades. The wheel is rotated rapidly, 

 thus causing the circulation of the whole mass and, by agita- 

 tion, the separation of the rubber and bagasse which still 

 remains a.ssociated with it. The now entirely clean rubber 

 is finally run through a pair of finely corrugated steel rollers, 

 which sheets it. In this condition it is ready for the market 

 and is shipped in 200 tt>. sacks. 



THE EXTRACTION OF RUBBER FROM 



THE GUAYULE PLANT. 



The following account of the e-\traction of rubber 

 from the Guayule plant (Parthcniuiii argentatum) is 

 taken from the Journal of the New York Botanical 

 Garden for May 1911:— 



The guayule plant {Partlienmiu avijentatuiii) occurs in 

 the central plateau of !Me,xico, and in its extension, the 

 Stockton plateau of Texas. There has recently been 

 established at Marathon, Texa.s, a factory for the manufac- 

 ture of rubber from the plants which grow in that vicinity, 

 embracing the whole of the area of distribution in Texas. 

 The more imi)ortant steps in the process of manufacture are 

 as follows: — 



The shrub is collected in the field by pulling it up by 

 hand. It is then brought to a central point, called a guayule 

 camp, where it is packed into bales in the fashion of baled 

 hay. From this point, it is hauled to the factory, a distance 

 of 50 to 100 miles, according to the location of the camp. 

 Arrived at the factor}-, the weight of each bale is recorded 

 for the purpose of comparison with the field weight at the 

 time of baling, and for the purpose also of establishing data 

 so as to show the percentage of returns. The bales are 

 stacked in the factory yard until seasoned, since the extrac- 

 tion does not go on well if the fresh shrub is used. 



The first step in the actual factory process is a cru,shing 

 of the shrub between corrugated rollers moving at differen- 

 tial speeds. The comminuted shruli is then placed in 

 a pebble mill. This is a short drum, containing a charge of 

 Norwegian or Mediterranean flint jiebbles, a certs in amount 

 of water and the amount of shrub to be ground. The mill 

 is rotated on its axis at a certain rate of speed for a certain 

 length of time, at the end of which the shrub is found to be 

 finely ground and the rubljer more or less separated from the 

 bagasse, that is, the fibre, etc., of the shrub, and occurs 

 in the form of small rounded particles, more or less adherent 

 to each other, called 'worm-rubber'. The mill is now 

 discharged, the water, rubber and bagasse being led through 

 ditches to a skimming tank 



The material in part sinks, namely the waterlogged 

 fibrous bagasse, and in part floats, the rubber, or rather 

 the chief portion of it, and cork bagasse. It is thus 

 that in the skimming tank the major portion of the 

 ground shrub is separated from the rubber, which floats 

 and is accompanied by flakes of cork (cork bagasse). The 

 fibrous liagasse is then discharged, the floating material 

 (rubber and cork bagasse) is boiled for one hour and then 

 allowed to remain one or two days in a .settling tank. The 



THU; USE OF MANURES IN FORESTRY. 



This subject receives attention in a note in the Journal 

 of the Board of Aijricidture for May 1911, p. 137, based 

 on a paper presented at the Sixth International Forestry 

 Congress at Brussels. It was pointed out, in this, that the 

 importance of manuring is by no means as great in forestry 

 as in agriculture, for the following reasons ; (1) the amount 

 of mineral salts retained in timber is comparatively small; 

 (2) there is a long period of time intervening between the 

 planting and felling of the forest; (3) the fall of leaves and 

 twigs causes the trees to return the greater part of their min- 

 eral constituents to the soil; and (4) the available mineral 

 matter in the soil is continually, but slowly, replaced by its 

 decomposition. As regards the Continent of Europe, the old 

 forest soils are usually sufliciently rich in mineral salts, and 

 remain so under the present system of forestry. An objec- 

 tion to artificial manuring, in itself, is that it increases the 

 cost of planting by 50 to 100 per cent., with no possibility of 

 return before the trees are cut down. 



Where manure is required, there is the difficulty in the 

 case of middle-aged wood because of the depth of the roots; 

 experience shows that the method to be adopted in this case 

 is to haste;i the decomposition of the fallen leaves and twigs, 

 either by mixing them with the soil, or by applications of lime. 

 Irrigation with sewage water has given varying results. 

 A form of manuring in which the soil was covered with 

 a layer of city refuse 8 inches thick has been tried by the 

 city of Berlin, with much success. 



Artificial manuring for forests is of the greatest impor- 

 tance with young plants growing in poor, sandy soils. Here 

 the soil may be enriched by planting leguminous plants; 

 dressing it with turf and other substances containing humus — 

 a method that has given very good results; covering the soil 

 with waste vegetable matter; and employing a species of tree 

 having a heavy leaf fall, for interplanting. There is added 

 to these methods that of planting, with the other trees, legu- 

 minous forest trees. (.Quickly acting nitrogenous manures are 

 useless in ordinary circumstances, except where the soil has 

 deteriorated or where the trees require to be carried over 

 some critical period such as that subsequent to their sufteriog 

 damage from any cause. 



Attention is drawn to the fact that, in the fortnightly 

 report on the produce markets, issued by Gillespie Bros, k Co., 

 dated .June 20, 1911, a quotation is given for: 'really fine 

 clear, concentrated lime juice, suitable for direct use ia 

 calico-printing.' 



