Weight. — The Technical Anabjsis of Sliped Wool. 



43 



The methods of analysis in a works-laboratory must of necessity be 

 rapid, but at the same time reasonable accuracy must be assured, otherwise 

 the method is valueless. 



As far as the author can find, no methods of wool-analysis requiring 

 thejabove determinations have as yet been published, so the following 

 methods were devised to meet the requirements of a works-laboratory in 

 which the chemical control of wools is carried out. 



All that is claimed for the following methods is that they meet the 

 requirements of a works-laboratory, and that, while they give accurate 

 results, they are rapid, and the condition of the wool can be reported before 

 a consignment is baled for shipment. 



Moisture is determined in 1 gram by drpng in an air-oven at 110° C. 

 for one hour. After removal from the oven the sample must be placed in 

 a desiccator under vacuum, and, after coohng, be weighed rapidly to pre- 

 vent the absorption of atmospheric moisture, which, on account of the 

 hydroscopic nature of wool, is readily taken up. 



Natural wool-fat is determined in 2 grams of the material by extraction 

 with hot alcohol. An aliquot portion of the liquid is evaporated to deter- 

 mine the total fat extracted ; in another portion determine the free fatty 

 acidity, using phenolphthalein as the indicator. After deducting the free 

 acidity from the total fats, the balance is considered natural wool-fat. 



In another portion of the material extract the total fats with petroleum- 

 ether, and after deducting the natural wool-fat the balance is entered as 

 " other fatty matter." After drying the wool substance used in the pre- 

 vious determination, weigh. The sand, dirt, and Ume may be approximately 

 determined by shaking out mechanically the adhering particles after the 

 total-fat extraction, and, after washing in hot alcohol and drying, the loss 

 on again weighing is entered as sand, lime, and dirt. The remaining sub- 

 stance is wool-fibre, and is entered as such. 



The following are examples of analysis of sliped wools carried out as 

 described : — - 



Leicester. 



Lincoln. 



Three-quar- 

 ter-bred. 



Half-bred. 



Seconds. 



Tliirds. 



Moisture 

 Natural wool-fat 

 Other fatty matter 

 Sand, dirt, and lime 

 Wool-fibre 



Per Cent. 



11-08 



7-28 



1-62 



10-30 



69-72 



100-00 



100-00 



100-00 



Per Cent. 

 11-70 

 12-06 



0-72 



8-14 



67-38 



100-00 



Per Cent. 



12-80 



3-68 



1-56 



12-26 



69-70 



100-00 



Per Cent. 

 12-74 



11-90 



19-08 

 56-28 



100-00 



It should be noted that scoured wools, or wools washed with soap, cannot 

 be examined for natural wool-grease by the method stated above, for the 

 reason that all scoured wools retain some of the soap used, which is soluble 

 in alcohol. The analysis of " thirds " shown above is an example of scoured 

 wool. 



For permission to publish these results I have to express my thanks 

 to the Christchurch Meat Company (Limited). 



