. Annals of the New York Academy of Sciences. Science. Method of Cutting Sections at Right Angles to the Acute Bisectrix. In cutting sections of the crys- tals for the purpose of measuring the axial angle some difficulty was at first experienced in getting the section cut at just the desired angle, as no saw for sectioning brittle minerals in any desired direction was at hand. The fol- lowing method was devised and on account of its simplicity and the uniformlj^ good results ob- tained seems worthy of mention. A frame of hard polished steel was made of the shape, shown in the upper part of Fig
. Annals of the New York Academy of Sciences. Science. Method of Cutting Sections at Right Angles to the Acute Bisectrix. In cutting sections of the crys- tals for the purpose of measuring the axial angle some difficulty was at first experienced in getting the section cut at just the desired angle, as no saw for sectioning brittle minerals in any desired direction was at hand. The fol- lowing method was devised and on account of its simplicity and the uniformlj^ good results ob- tained seems worthy of mention. A frame of hard polished steel was made of the shape, shown in the upper part of Fig 1. On the clinopinacoidal face, or a ground -plane corresponding to it, there is scratched a line representing the trace of a plane normal to the acute bisectrix. The crystal is then fastened in the frame with a piece of wax so that the line coincides with the upper surface of the frame, and plaster of paris poured in around it and allowed to harden. The crystal is thus firmly embedded in the frame as shown in the lower cut of the figure, and is ground down until its surface is even with that of the steel frame. The crystal is then removed, the ground surface polished and cemented to a glass slip and the other end of the crystal ground down in the usual Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original New York Academy of Sciences. New York, New York Academy of Sciences
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectscience, bookyear1877
