A developmental pilot line for the arc treatment of Colorado rhodonite has been built and operated to investigate the applicability of the high-intensity arc process to the extraction of manganese from siliceous ores. The rhodonite is incorporated into 2-in. diameter electrodes to the extent of 75-85% by weight and vaporized in a d-c high-intensity arc operating in the range 40-60 kw. Vaporization in the arc decomposes the manganese silicate content of the rhodonite to MnO and SiO~. The product is collected as a mixture of the respective oxides in finely particulated form. The manganese, now readily soluble, is leached from this mixture. The effects of significant process variables are discussed.This paper describes the design and operation of a developmental pilot plant for the arc decomposition of Colorado rhodonite by means of a new process known as the Sheer-Xorman "Hierarc Process" (1, 2). The primary purposes of this program were to demonstrate the technical feasibility of treating rhodonite and to obtain process design and evaluation data.Rhodonite, a manganese silicate, is found in several sections of the United States and abounds in the southwestern area of Colorado. While deposits represent a significant quantity of Mn, the material is of such a refractory and stable nature that it has never been used as a major Mn source; instead it has been described as worthless gangue material in lead and zinc mining operations. Theoretically, pure rhodonite contains 42% Mn. Mined and milled in conjunction with lead-zinc operations, concentrates ranging up to 33, or perhaps 36% Mn, might be expected.The Hierarc Process, utilizing the high-intensity arc, serves to decompose the manganese silicate into a mixture of two discreet, finely particulated materials, manganous oxide and silica. In this form, the Mn is readily dissolved by leaching. For example, over 95% of the Mn in samples of arc product dissolved in dilute HC1 at room temperature.Using an anode consisting of an homogeneous mixture of ore and carbon--the ore content may be as high as 80-85%--the high-intensity arc provides an effective means of heating the material to temperatures of decomposition without the necessity of heating crucibles or other containing vessels.

The technique of producing ultrafine powders by vaporization in the highintensity arc has been applied to a number of refractory materials, including oxides, carbides, and metals. Particle size ranges of the products obtained lie generally between 100 and 1000A. Following a brief resume of the processing technique, a description of particulate characteristics is presented. Such properties as average size, shape, size distribution, sinterability, and chemical reactivity are examined, chiefly by electron microscopy, x-ray diffraction, sintering tests, and solution rates.

The energy dependence of slow neutrons scattered from a thick gold target has been measured using a newly developed scattering chamber in conjunction with the Columbia slow neutron velocity spectrometer. A method of analysis has been developed for determining the ratio of the scattering cross section to the total cross section, a 8 /

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This paper surveys classical Jewish texts--from the Hebrew Bible through Medieval codes--regarding the concept and practice of Bikkur Holim, literally, "the sick visit." How does this literature understand this ethical, religious act; who are the practitioners; what are their objectives? Although the Hebrew Bible does not contain a biblical precedent or legal mandate for Bikkur Holim, various categories of pastoral actions are traced in midrashic and talmudic texts. Their nuances are examined closely and a conceptualization of Jewish pastoral care is identified in a work by thirteenth century rabbi, jurist and physician, Nahmanides. Ezekiel 34 is proposed as the source for the rabbinic term, Bikkur Holim, as well as the conceptual understanding of Jewish pastoral care. Finally, the author posits various questions regarding the implication of his findings on the conduct of Jewish pastoral care, the value of spiritual assessment, and the nature of chaplaincy work in our various religious traditions.