dc.description.transcription | NATIONAL MUSEUM of NATURAL HISTORY SMITHSONIAN INSTITUTION 29 September 1994 202) 357-1478 Dr. Tim McCoy Code SN4 NASA Johnson Space Center Houston, TX 77058 Dear Tim: I am enclosing the following material that you requested: Bluff, Texas USNM 135-1 Cedar (Texas) USNM 240-1 Travis County, Texas USNM 145 PTS PTS 1352 g The two thin sections are on loan to you for six months. The Travis County specimen is on loan to you for one month with the following stipulations: (1) it is to be handled only with gloves, (2) no material will be removed, and (3) no destructive analysis of any kind will be performed on the specimen. We also request that you return it registered mail packed very carefully in the same plastic box. When you receive the shipping invoice that is being sent under separate cover, please sign, date and return the indicated copy. Please refer to any Smithsonian samples by their USNM numbers in publications arising out of your work, and acknowledge the Smithsonian as the source of the material. We would also appreciate receiving copies of any reprints for our files. Sincerely yours, Linda Schramm Division of Meteorites, MRC 119 CARE AND CONDITIONS FOR USE OF NMNH METEORITE THIN SECTIONS In order to assure that our thin sections have the maximum possible availability and that they remain in the best possible condition for all possible future uses, we ask borrowers of our sections to please observe the following guidelines. 1. The normal loan period for thin sections is 6 months; extensions must be requested in writing. When sections are returned to us, they should be returned by registered mail. 2. The condition of the thin sections generally reflects the care given them by the previous users. Even with ideal care, however, the sections ultimately require repolishing and recoating. We prefer that such repolishing be done here. However, borrowers may request to do this if it is necessary, providing they have the proper facilities to do so. If there is any doubt, feel free to return the sections to us and we will have the sections processed here and returned. If sections show signs of peeling off of the glass slide, please do not attempt to repolish them; return them to us. 3. Only carbon paint is acceptable for conductivity purposes, and its use should be kept to a minimum. Silver paint can never be entirely removed from the sections, and its presence renders them unsuitable for future use in scanning electron microscopy. Specks of silver will show up as bright specks all over any photographs, especially in poorly polished areas of the sections. 4. Only carbon coatings are acceptable on the sections. Gold coatings are specifically forbidden. As in the case of silver paint, gold coatings make the sections unsuitable for future use in electron microscopy. Carbon coatings have proven entirely satisfactory for ion probe purposes. 5. Publications resulting from the use of our samples should cite the U.S. National Museum of Natural History as the source of the samples, and refer to the samples by their proper. NMNH numbers. As a favor, we ask that you please send one copy each of any publications to us for the Division files; these should be addressed to Linda Schramm Department of Mineral Sciences, NHB 119 Smithsonian Institution Washington, D.C. 20560 6. For any further information, please contact Linda at (202) 357-1478. 1/24/94 | |