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Calgon
226
CURRENT ToPIcs.
[J. F. I.
Tagging Fish.--(White Metal News Letter, Sept. I933.) It may not be difficult to tag a fish but Dr. Rounsefell in charge of the Alaska Herring Investigation for the U. S. Bureau of Fisheries has had his difficulties in the past when he tried to recover the tags. The fish are tagged for the purpose of tracing their migration which is done by recording the points at which the fish and their tags are caught. Since the herring and the tags are quite small, ordinary methods of tag recovery prove rather tedious. Accordingly, Dr. Rounsefell has developed a magnetic nickel tag and has installed a system of electro-magnets for recovering the tags. The great majority of the herring in Alaska are put through reduction plants for the manufacture of fish oil and fish meal. A powerful electro-manget was installed at the discharge end of each of the meal dryers and as the dry meal emerges from these cylinder dryers, it falls over the magnet, which catches the tags. C. Soldering Aluminum Successfully.--(/. & E. Chem., News Edition, Sept. 2o, I933. ) H . A . G . Gunnelius and G. Kraft of the Technologic Institute of Stockholm, Sweden, have developed a procedure for soldering aluminum with tin and other solders. The chief difficulty encountered when soldering aluminum is to obtain a surface absolutely free from oxides. Since commercial aluminum and most of its alloys contain more or less silicon, the surfaces to be soldered are cleaned with hydrofluoric acid or with solutions developing that acid. The acid must be carefully removed by washing with water and the water then removed by dipping the metal into alcohol, preferably methanol. Any solder may be used and if the corrosion resistance of the connection is not very important an alloy of 85 per cent. tin and I5 per cent. aluminum is satisfactory. Where corrosive conditions are encountered a higher melting-point solder should be used--for instance, 90 per cent. aluminum, 9 per cent. copper and I per cent. silver. Calgon.--The Mellon Institute of Industrial Research announces the induction of a fellowship providing for research upon molecularly dehydrated phosphates of alkali metals. Calgon, a member of this group, is essentially sodium metaphosphate. This product is found to be of utility in cleaning various constructional materials, including stone, brick and terra-cotta. It also is satisfactory for cleaning shrubbery and trees begrimed with smoke and soot. Calgon also appears to have some solvent effect upon residual calcium soaps. C.
CURRENT ToPIcs.
[J. F. I.
Tagging Fish.--(White Metal News Letter, Sept. I933.) It may not be difficult to tag a fish but Dr. Rounsefell in charge of the Alaska Herring Investigation for the U. S. Bureau of Fisheries has had his difficulties in the past when he tried to recover the tags. The fish are tagged for the purpose of tracing their migration which is done by recording the points at which the fish and their tags are caught. Since the herring and the tags are quite small, ordinary methods of tag recovery prove rather tedious. Accordingly, Dr. Rounsefell has developed a magnetic nickel tag and has installed a system of electro-magnets for recovering the tags. The great majority of the herring in Alaska are put through reduction plants for the manufacture of fish oil and fish meal. A powerful electro-manget was installed at the discharge end of each of the meal dryers and as the dry meal emerges from these cylinder dryers, it falls over the magnet, which catches the tags. C. Soldering Aluminum Successfully.--(/. & E. Chem., News Edition, Sept. 2o, I933. ) H . A . G . Gunnelius and G. Kraft of the Technologic Institute of Stockholm, Sweden, have developed a procedure for soldering aluminum with tin and other solders. The chief difficulty encountered when soldering aluminum is to obtain a surface absolutely free from oxides. Since commercial aluminum and most of its alloys contain more or less silicon, the surfaces to be soldered are cleaned with hydrofluoric acid or with solutions developing that acid. The acid must be carefully removed by washing with water and the water then removed by dipping the metal into alcohol, preferably methanol. Any solder may be used and if the corrosion resistance of the connection is not very important an alloy of 85 per cent. tin and I5 per cent. aluminum is satisfactory. Where corrosive conditions are encountered a higher melting-point solder should be used--for instance, 90 per cent. aluminum, 9 per cent. copper and I per cent. silver. Calgon.--The Mellon Institute of Industrial Research announces the induction of a fellowship providing for research upon molecularly dehydrated phosphates of alkali metals. Calgon, a member of this group, is essentially sodium metaphosphate. This product is found to be of utility in cleaning various constructional materials, including stone, brick and terra-cotta. It also is satisfactory for cleaning shrubbery and trees begrimed with smoke and soot. Calgon also appears to have some solvent effect upon residual calcium soaps. C.