Albany Advertiser (W. Australia)
Every plant (says “Chamber's Journal”) contains a large proportion of carbon in its composition and this element is now generally admitted to be derived from the atmosphere by means of the leaves, in spite of the very small proportion of carbon, 30 per cent., to be found in fresh air. It is only reasonable to suppose, therefore, that by increasing the percentage of carbon acid gas, known by chemists as C.O. in the air around growing plants, their growth will be accelerated. But in order to make such a method commercially successful, a cheap and abundant source of carbonic acid gas must be found. As is well known, the gases escaping from all fires contain this gas; but a particularly large proportion distinguishes those discharges from blast-furnaces. Founding on this fact, Dr. Riedel, of Essen-on-Ruhr, has patented a process whereby growing plants are supplied with blast-furnace gases after they have been, purified from their noxious constituents, such as sulphur. In order to test the process, a greenhouse was supplied with the purified gases by a number of pipes, these being run backwards and forwards over the whole length of the room, and punctured at intervals for the escape of the gas. Two other greenhouses, without any gas supply, were tested at the same time to obtain comparative results. Experiments were begun about the middle of June. The effect of the gas upon a castor oil plant was to produce leaves more than a metre in width, whereas in the two other greenhouses the leaves reached only about half that size. Tomatoes increased in weight by 175 per cent. Open-air experiments were also tried in suitable plots of land, around one of which was a pipe with holes at intervals, through which the carbonic acid gas was continually escaping. CO, being heavy, would, of course, lie along the surface of the ground. In the open air the yield of spinach was found to be greater by 150 per cent in the gas-supplied plot, while potatoes increased by 180 per cent., lupines by 174 per cent., and barley by 100 per cent. Later tests on a much larger scale have shown an increase in a potato crop of 300 per cent. According to the inventor's opinion, as set forth in the “Scientific American,” carbonic acid gas works for supplying agriculture will before long be quite a common a feature as electricity and gas works, the large industrial centres at the same time becoming centres of increasing agricultural production. Careful analysis has shown that no danger to the health of man is threatened by the additional amount of carbonic acid gas contained in the air where the system is in vogue.
H/t to Steven Goddard.