Om Materialprøvningens Udvikling i Norden
Og om Statsprøveanstaltens Virksomhed

V * 'V » - SX " 175 On this base the colours were to the first class, that one most belong chiefly such protective here that came to oil varnish had been used as a medium I112 kg sand and hoisted up to such a height, that the distance from the tap-hole to the plate f was about 21j2 m. Then the painted iron plates were placed on the disc f, d was removed by a rash pall in the string, and the sand began to fall, finally being picked up in C after working upon the painted plates. — As the case might be, this proceeding could be repeated several times with the same plate. For the experiment were employed 2 different sorts of sand, partly Berlin-Normal sand (Sand I), partly down sand where the grains were of such a size that it passed through a sieve with 400 meshes pr. sq. cm, but was retained by one with 900 meshes pr. sq. cm (Sand II). On a colour proving, namely, to be immediately worn through when employing the first named sort of sand the smaller size of grains was tried, placed in 4 classes. We shall only state capable of resistance, coatings where linseed which is beyond all doubt due to the elasticity of the linseed oil varnish, thus the same fact which makes linoleum last so well against sandblast jets. The medium being fragile, the coating springs off more easily when hit by the jet of sand. The report of the wear-experiments, dealt with here, and of which a summary is only given here, has for the rest been trans- lated in extenso into German in »Baumaterialienkunde« 1905, p. 168. There it is also set forth that a jet of sand was presumably employed for the first time for wear experiments -— especially on wood — in this country (see the research published in 1893, and mentioned above, by Mr. C. V. Meldahi, graduate in forestry and civil-engineer), and reasons are also established why sandblast is hardly adapted to wear-experiments with wood. For wear-ex- periments with protective coatings the sand-blast seems to be more appropriate as, for instance, the paint on stays for electric tram- ways is no doubt much worn off by drifting dust and sand. As of Report XII only the short section on the wear-experi- ments has hitherto been translated into a foreign language this report has presumably, apart from this, remained unknown ex- cept in the Scandinavian countries where the Danish language is understood. From an Annual Report from the Testing Laboratory in Stockholm it appears, indeed, that this Laboratory has adopted ■i ....