AGRICULTURAL MACHINERY AND IMPLEMENTS 1 33 1 



that it undergoes far smaller losses during the process of extraction, which, 

 in addition is carried much farther : while carbon bisulphide leaves up to 

 4.5 % of oil unextracted, with the use of the tetrachloride this loss does not 

 exceed 1.6 %. Finally this solvent very readily gives up the oil extracted 

 (with which it does not form an emulsion as does carbon bisulphide) and, 

 if the seeds or other oily substances to be treated are not deteriorated, an 

 oil as good as if extracted by pressure is obtained. 



The essential part of the apparatus in question is an extractor A in 

 which a metal gauze basket is suspended containing the oily matters to be 

 subjected to extraction, broken up to allow of easy access to the solvent. 

 The latter circulates from below upwards by means of the leaching-tube 0, 

 and thus effects the extraction of the oil in the form of a solution which 

 gathers at the bottom of the extractor. The vapour of the solvent, rises 

 through the pipe H, and is then conducted through the pipe M to B, where 

 it condenses in a coil cooled with running water. By using the tap P, the 

 condensed solvent may be made to return to the extractor, or through the 

 pipe I it way be made to pass into the tank C. 



When the extraction is completed, the extractor (placed on a furnace) 

 is heated either with an open fire, or in a water bath in the case of delicate 

 oils. In this way the bulk of the solvent is eliminated from the oil solution 

 collected at the bottom, and afterwards, in order to remove the last traces, 

 hot air is injected into the extractor by means of a small force pump. 

 When this is done, the oil can be drained oft' by opening the tap R. 



The waste heat of the furnace is used to heat the drier D, where the 

 broken up oily material is kept for some time before extraction. 



The apparatus being airtight the losses of solvent are very small. 



To accelerate the work and make it continuous, the apparatus is made 

 with 2 extractors, one of which is in operation while the other discharges 

 and recharges for the next operation. 



The appliance is easily managed, and does not require more than 2 

 workmen. 



1007 -Appliance for Burning Tree Stumps fn situ. — Scientific American, \\a. cxiv, 



No. 25, p. 6 13, I fig. New York, June 17, 1916. 



This appliance, which is termed a " stump-burner ", being a sort of 

 portable stove for charring and destroying wood, was recently tried with 

 success by a large forest working company in Mississipi (United States). 



It is placed on a stump, and the latter subjected to slow combustion 

 until completely charred, during which time the heavy oils (heavy products 

 of dry distillation) are collected. When these operations have been com- 

 pleted on one stump, they are repeated on another, by carr>dng the appara- 

 tus to it, and so forth. 



This contrivance is capable of rendering great service on cleared forest 

 land to be brought under cultivation, as it greatly facilitates clearance, 

 which the laborious rooting up of the stumps by ordinary means generally 

 makes so expensive ; it destroys the stumps to a sufficient depth to allow 

 of ploughing without needing to cut roots or carry out any preparatory soil 



