Leaf Sheath: The stomatal guard cells in the grass Hor-deum vulgare are normally formed by a regular and predictable sequence of cell divisions. It was found, however, that it was possible to alter the direction of the mitotic spindles of the guard cell mother cells by administering 2-mer-captoethanol (a sulfur-containing derivative of ethyl alcohol) to the leaf sheath so that the cells were parallel to the leaf axis instead of trans¬verse. Excision of the leaf sheaths also resulted in a few reoriented divisions. Both treatments presumably depressed nucleic acid synthesis in the guard cell mother cell. While the synthesis was depressed, the cell continued to elongate with the other cells until the oriented large molecules were irreversibly moved. The two methods were the result of efforts to explain cell polarity.
Metal leaf. The use of silver and gold leaf surfaces in Decoration has become popular in recent years. These effects are also part of the painter's work. Aluminum leaf is generally used in place of silver, as it is less expensive and does not tarnish. The application of metal leaf is accomplished by first applying a gold size to the surface to be treated. This is allowed to dry to a thick consistency, and the leaf is then applied to the size and allowed to dry thoroughly. It is best to varnish metal leaf for protection. Metal leaf is usually glazed over the varnish for antique effects.See Also Vacuum Leaf:Cutting, repacking with parchment, and beating are continued until the desired thickness of leaf is obtained. The finished leaf is cut into 3%-inch (8.5-cm) squares, which is the standard size of a sheet of gold leaf. Gold leaf for decora¬tive purposes can also be produced by electroly¬sis, cathode sputtering, and vacuum leaf vaporization.
This sheet is cut into 2-inch (5-cm) squares, which are interleaved with larger square sheets of parchment and hammered by hand or machine down to a thickness of about 0.0004 inch (0.001 cm). Cutting, repacking with parchment, and beating are continued until the desired thickness of leaf is obtained. The finished leaf is cut into 3%-inch (8.5-cm) squares, which is the standard size of a sheet of gold leaf. Gold leaf for decora¬tive purposes can also be produced by electroly¬sis, cathode sputtering, and vacuum leaf vaporization.
On The Other Hand See Earl Leaf And His:Your travel pictures will fall almost altogether into two categories, stock pictures and picture stories, and there is more detailed information on how to sell such pictures in later chapters.
Before we drop the subject of travel pictures, it might be well to clarify something which might seem contradictory, the incident mentioned concerning Earl Leaf and his big earnings from one week of shooting in Paris, as set against the later advice to take your time and to learn all about the area to which you travel. You see, Earl Leaf, while waiting for just the right weather for his shooting, spent three months in Paris studying the city.
An inspiring example, though hardly typical, of what can be accomplished by a roving cameraman is supplied by Earl Leaf, the versatile magazine photographer. During just one week in Paris when the weather was just right for pictures, Leaf covered the landmarks of the city with two Rolleiflexes, one loaded with black-and-white film and the other with color, and to date he has netted roughly five thousand dollars for that week's shooting, and the pictures are still selling.
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