Blackening Process Research Articles

The foraminiferida of the Persian gulf. 5. The shelf off the trucial coast

The foraminiferids are described from three profiles across the shelf north of the Trucial Coast of the Persian Gulf. Living foraminiferids are absent from the sediment surface. The dead foraminiferids are abundant and show evidence of transport. The smaller foraminiferids are closely related to those of the coastal complex. The larger forms have not been observed in the coastal complex and their source area must be on the shelf. Black foraminiferids are present in some samples. The blackening process preferentially affects the Miliolacea and Lituolacea and most of the black specimens are larger than the average non-blackened forms.

Alchemy in Reverse: Robert Boyle on the Degradation of Gold

A LCHEMY was ordinarily considered to have as its ultimate objective the perfection of metals, in particular, the making / ^ of silver and gold out of the baser or less perfect metals. Various accounts appear in the literature of claims for successful pro jections, usually with the aid of a mysterious powder. In some direc tions for making transmutations the base starting materials are de graded in a preliminary step in order to deprive them of any qualities, an operation called melanosis. Except for this initial blackening proc ess, alchemists concerned themselves with the process of perfecting metals. In fact, certain authors have alleged that there are no accounts of operations in which a noble metal has become debased. For this reason, it is appropriate to examine the little-known tract of Robert Boyle, Of a Degradation of Gold, published in 1678.1 Although the author of this seventeen-page book was simply listed as an Anti-Elixir, Boyle's pen was accepted by his contemporaries as the source and his name appeared on the title page of the second edition.2 Only a few copies were printed and Fulton knew of only four extant copies when he prepared the second edition of his bibli ography of Boyle's works. The second edition, which bears the en

Studies on the Resistance of Japanese Pear to Black Spot Disease Fungus (Alternaria Kikuchiana TANAKA) III.

1. By means of cultural method the BAVENDAMM'S reaction of Alternaria Kikuchiana, a causal fungus of black spot disease of Japanese pear, is positive on its culture media. The writers have also found the laccase (polyphenoloxidase) reaction in the fungus-free filtrates of potatodecoction culture, showing blue color with guaiacum tincture. However, we did not find tyrosinase in them.2. The optimum pH value of polyphenol-oxidase produced by the present fungus lies approximately at 8.0-8.3, using PARITZSCH'S borate buffer. When potatodecoction media containing 2% sucrose was used, the maximum value of Oxidase activity was obtained in 12 to 14 days after inoculation, but after about 30 days it was negligible. It is assumed, therefore, that the Oxidase activity is parallel th the growth curve of the mycelium. When different amounts of sugar was added to the media, the activity was most intensive in the culture solution containing 2% sugar, having no connection with the dry weight of the mycelium.3. When the culture filtrate was dialysed through collodion semipermeable membrane, we found that the enzyme solution that remained in the bag did not cause the death of leaf tissue and the toxic substances contained in the solution outside the bag, had the ability to cause the death of the tissues showing black appearance.4. Among the fungi belonging to the genus Alternaria, it was found that some species had positive reaction of Polyphenol-oxidase in their fungus-free filtrates of culture media. Many of them, however, do not attack pear leaves, thus there is no resulting necrosis of cells.5. From the result of the above stated investigations, it was concluded that Polyphenol-oxidase produced by the present fungus did not cause the death of tissues in leaves and fruits of pear directly. It is presumable, however, that Oxidase has some connection with the process of blackening of the lesions.

林檎果汁變色防止に就て

林檎切片及び果汁の變色を防止する藥劑を其の10%液を林檎パルプに滴下放置する事により試驗した結果98の藥劑中總ての鹽化物, 亞硫酸鹽及び明礬の或る物が有効である事が判つた。

The Blackening of Zinc Sulfide Phosphors

The process of blackening of zinc and cadmium sulfide phosphors is studied experimentally and theoretically. A survey of the principal experimental facts is given and several new experiments are described. It is suggested that the blackening of the sulfide salts is a two-quantum process in which both positive and negative charges are released from the interior; these charges move to the surface and there produce electrolysis in a film of moisture that is present on the surface when the specimen is in damp air. This picture will explain the known experimental facts concerning the blackening process. The important differences between the blackening of sulfides and the print-out effect in photographic emulsions are discussed.