Paper, tests paraffins

Spot colorimetry can be conducted on spot plates, comparison spot plates or on filter paper. The use of confined spot reactions, as introduced by Yagoda, is particularly practical. He has described the impregnation of suitable spot test papers with paraffin rings that serve as barriers to the spread of the flecks. Such papers are on the market and provide the added advantage that spot flecks carried out with known amounts of the material... 

The wrapping of the explosive charge, e.g. paraffined paper, parchment paper, tinfoil etc. (this factor was tested over a long period and some of the results are discussed further on p. 424). 

Ground (but not powdery ) fused Se (10 g.) is placed in a 100-ml. test tube. Then 50 ml. of Tetralinis added, together with 5 g. of white P wire which has been quickly dried with filter paper. The lower end of the test tube is immersed in a paraffin bath (215-220°C). As soon as the P melts, the tube contents are mixed with an L-shaped rod imtil the mass acquires a imtform consistency. The tube is then lowered into the bath so that all the Tetralin is surroimded by the paraffin and begins to boil. At a... 

Samples for grain structure studies were cut from both tensile and impact specimens after they had been tested at 76 and 300 K. Electrolytic polishing of samples gave the best results. A solution of one part perchloric acid to four parts ethyl alcohol with a potential of 30 volts was used. The specimens were first sanded with 000 paper using a lubricant of paraffin dissolved in kerosene and then polished on selvyt cloth with levigated alumina before electrolytically polishing. 

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