29 August 1942

Out twice today from 9.15 to 10.30am  for walk around and again from 4.10 to 4.45 pm walk and ball game.  Some more people have arrived.  Fighting Mieck included.  No extra food after today, I am informed.

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The manufacture of Sole Crepe is a special operation.  Sole Crepe, as the name implies, is the rubber used for the soles of tennis shoes etc.  It is possible that, since my time on Langen, manufacturing methods have changed.  On Langen strips of ordinary Crepe were built up one on top of the other, on tables specially designed for the purpose, until the required thickness was attained.

The strips, or laminations to give the technical name, were caused to adhere to each other by forceful slappings of the open hands applied to each strip as it was stretched out on the table.  It should be explained that even pressing two pieces of Crepe together is sufficient  to cause them to adhere strongly to each other.  By beating with the open hands, the strips became, as it were, welded together into one thick sheet.  The necessary laminations having been thus stuck together, this thick sheet was then passed through a pair of heavy rollers where the intense pressure completed the operation of producing Sole Crepe ready for use.  Sole Crepe was manufactured in thickness of 1/8, 3/16 or 1/4 inch and experience had taught the exact number of laminations to be slapped together in order to produce the required thickness when milled.  As an example of the strength of the Langen product, I may mention that in 1927 I had made for me a pair of sandals soled with Sole Crepe made under my supervision and these sandals I threw away only a few months ago and only then because the lether had at last given way.  In spite of my having worn the sandals regularly every day for 15 years, the rubber soles showed only moderate signs of wear.  One of the difficulties connected with manufacture was a water shortage during the dry season.  Ordinarily, water from the Tjutandoei river was pumped along a pipeline to a deep concrete reservoir in front of the factory.  This water was then pumped up into a water tank situated on a skeleton tower about 60 feet from the ground thus ensuing by gravity the pressure required to supply the faucets in the milling batteries and the many other points throughout the building.  During very dry seasons, however, the river fell so low that the inlet of our pipeline was left high and dry some feet above the stream.  We always had the reservoir to fall back upon but that supply was, of course, not inexhaustible so that a continued drought could have very seriously interfered with the manufacture.  For many years, therefore, experimental boring was carried out in the hope of striking a subterranean source of supply but without success until, in spite of repeated failures in the immediate vicinity, the manager with characteristic pigheadedness insisted on the engineer sinking a shaft just between the reservoir and the factory building.  Water was found, a pump rigged up and the precious element poured forth in a continuous stream.  I translated a glowing report to the company on the success which had at last crowned FV’s efforts.  It was only after the report had been dispatched that it was observed that, when the shaft pump was in action for any length of time, the water level in the reservoir fell and continued to fall the longer pumping went on.  Alas for FV’s hopes and his glowing report.  It was only too evident that the concrete basin of the reservoir had sprung a leak and that the supposedly tapped subterranean stream was nothing less than the seepage from that source.  It took, however, some three months of repeated pumping and observation to convince FV of the fact.