Om Materialprøvningens Udvikling i Norden
Og om Statsprøveanstaltens Virksomhed

179 seen from the side facing the fire and at p. 91 in fig. 34 from the side turned away from the fire. During the experiments the temperature was found to be about 700° Centigrade for the impregnated flakes, and about 50° Centigrade higher for the unimpregnated, but the statement of temperature must be considered rather uncertain. m. Testing of Linoleum and Jointless Floor-Coating Masses. In Report III of the Laboratory informations are given not only of the testing of linoleum etc. but also of its manufacturing and employment. The part of the report treating of the testing has been translated into German in »Baumaterialienkunde* 1901, p. 12. Here it is recorded that the wear-testing method commonly followed for bricks in a machine of Bauschinger’s or a like con- struction is not adapted to linoleum. On employing emery as wearing powder, it is namely pos- sible by this method to come to such abnormal and wrong re- sults as that linoleum holds its own better against wear than granite, which is due to the fact that something of the wearing powder can fix itself in the linoleum, so that the surface of the latter becomes coated with emery powder, but then it is not really the linoleum which is tested, but a material the surface of which consists chiefly of emery powder. By the method of the Laboratory for the testing of linoleum and jointless floor-coating masses such as papyrolith and the like to wear a wooden block coated with sand-paper is drawn to and fro across the material under a certain, light pressure, and at each 500th double stroke the sand-paper is changed; the latter must, of course, be of a certain fixed fineness becoming else too much filled or choked up. As dealt with more closely in the report of the Laboratory, it is possible at a very small expense to trans- form a simple American cold-saw into a wear-testing machine for linoleum etc. For the tests the linoleum is mounted on a piece of plate-glass. The imperfection of the method is willingly admitted and Geh. Regierungrat, Prof. Dr. Martens has in »Baumaterialien- kunde« 1901, Nr. 1 and 2, urged some objections against it, but the drawbacks may possibly be smaller than the advantages