142 AUTOBIOGRAPHY OF JOHN FRITZ
bands was about twenty-four inches, and as the uprights were about thirty inches apart, there were spaces or open¬ ings sixteen by twenty-two inches. This is known as the crinoline construction. By leaving a small hole in each space in whatever depth in the lining seemed proper, one could see and learn sometliing of the temperature in the furnace; should there be a scaffold, one could learn where it was; should the furnace be working hot in any place, it could be cooled off by the use of a swinging platform, which could reacUly be hooked to the band on any part of the furnace.
In the early seventies we built two more blast furnaces on new lines, seventy feet high and seventeen feet in diameter at the bosh. These furnaces were higher than those in general use. About this time coke began to be used in the furnaces in Western Pennsylvania and Eastern Ohio, and nearly double the amount of iron was made in the same sized furnaces that we could make with anthracite as a fuel. I thought that by building larger and higher furnaces and much more powerful blowing engines and by increasing the blast pressure from six to twelve pounds we could make as much iron in a given time with anthracite as they could with coke. Some of my Western friends came to Bethle¬ hem to see our new furnaces and learn how they were working. They were so weU satisfied with the result we had attained by high-pressure blast that they increased their blast pressure from about three and a half pounds to seven or eight, and we were again beaten about as badly as we had been before. We were the first, so far as I know, to use liigh-pressure blast.
The new blowing engines were made horizontal and were much criticized, but I paid Uttle or no attention to the critics. The engines, however, ran constantly for over thirty years, to my knowledge, day and night (which is