Phil Mag Research Articles

Effects of vacuum environment on the sub-structure of evaporated fcc metals films: L E Murr and M C Inman, Phil Mag, 14, 1966, 135–153

Etched insulated carbon fiber electrodes can be prepared from a suitable source of graphitized carbon fibers, copper wire, colloidal graphite, and a cathodic electrophoretic paint. The processes involved in the production of these electrodes involve mounting the carbon fibers, etching them to produce a sharp tip, and subsequent insulation of the tip so that only the very end of the tip is exposed. Etching of the electrodes requires a variable voltage AC source (50 Hz, 1–10 Vac), an AC current meter capable of measuring in the μA range and a suitable linear translation stage. Insulation of the electrode requires a DC power supply (0–20 V), linear translation stage, microscope, and oven. The insulation process involves two separate stages: electrophoretic deposition of paint onto the tip surface followed by a curing step at high temperatures during which the paint particles fuse together. Cathodic electrophoretic paint is the preferred polymeric material used to insulate the carbon fibers as the negative potentials required for deposition avoid any possibility of oxidative dissolution of the carbon fiber. Testing of electrodes requires a high-gain low-noise potentiostat. Testing is performed to determine the presence of any pinholes in the insulation. The quality of the coating of the electrode may be assessed in a nondestructive manner by measuring the diffusion limited current response as a function of the extent of immersion of the electrode into a suitable electrolyte solution. A more destructive approach to assessing the quality of the coating may be performed by polarizing the electrode in an electrolyte containing a suitable metal salt.

146. Effects of vacuum environment on the sub-structure of evaporated FCC metal films: L E Muir and M C Inman,Phil Mag, 14,1966, 135–154

146. Effects of vacuum environment on the sub-structure of evaporated FCC metal films: L E Muir and M C Inman,Phil Mag, 14,1966, 135–154

145. A study of nucleation in chemically grown epitaxial silicon films using molecular beam techniques. Part I. Experimental methods: B A Joyce and R R Bradley,Phil Mag, 14,1966, 289–300

145. A study of nucleation in chemically grown epitaxial silicon films using molecular beam techniques. Part I. Experimental methods: B A Joyce and R R Bradley,Phil Mag, 14,1966, 289–300

Effect of gaseous environment on the structure of sputtered GaAs films on NaCl substrates: T Evans and A J Noreika, Phil Mag, 13, 1966, 712–727

Effect of gaseous environment on the structure of sputtered GaAs films on NaCl substrates: T Evans and A J Noreika, Phil Mag, 13, 1966, 712–727

1771. Effect of gaseous environment on the structure of sputtered GaAs films on NaCl substrates: T Evans and A J Noreika, Phil Mag, 13, 1966, 717–727.

1771. Effect of gaseous environment on the structure of sputtered GaAs films on NaCl substrates: T Evans and A J Noreika, Phil Mag, 13, 1966, 717–727.

1430. The formation of imperfections in epitaxial gold films: M H Jacobs, et al,Phil Mag,13(121), 1966, 129–156

1430. The formation of imperfections in epitaxial gold films: M H Jacobs, et al,Phil Mag,13(121), 1966, 129–156

678. Epitaxial growth of silver and gold films by sputtering: D S Campbell and D T Shirland,Phil Mag, 9, April 1964, 703–707

678. Epitaxial growth of silver and gold films by sputtering: D S Campbell and D T Shirland,Phil Mag, 9, April 1964, 703–707

The growth and structure of gold and silver deposits formed by evaporation inside an electron microscope: D W Pashleyet al, Phil Mag, 10, July 1964, 127–158.

The growth and structure of gold and silver deposits formed by evaporation inside an electron microscope: D W Pashleyet al, Phil Mag, 10, July 1964, 127–158.

Change of Spacing of Positive Column Striations with Temperature

Cassen's prediction (Phil Mag. 268, 948, Nov. 1926 )that the separation of the striations in a discharge tube should increased almost linearly with the absolute temperature is verified for the wide blue striations. For the narrow striations, the separation first decreases, but in general reaches a minimum, after which the separation increases as predicted.

The Mountains and their Roots

MAJOR COWIE'S letter in NATURE of May 8 gives the impression that I had the facts of the observations on the deflection of the plumb-line in India before me, and that I made my assumptions as to relative densities, and the mode of compensation by extension of depressed crust beneath the plains, “suitably adjusted,” so as if possible to bring out the desired results. This was not the case. I made the assumptions about relative densities which seemed to be a priori probable; and it will be seen from the diagram at p. 184 of my “Physics of the Earth's Crust” that fifteen years before I wrote the paper in the Phil Mag. I had suggested that compressed mountains would be partly supported by an extension of the depressed crust beyond them.

Notes on the Sutherland Goldfield

1. Introduction Although a good deal has been written concerning the gold of Sutherland, it may be useful, as there seems to be a renewal of interest in the subject, to recapitulate the information actually obtained up to the present time, including a few additional points which came to light during the progress of the Geological Survey in the auriferous area. Verbal information of any value was difficult to obtain in the district itself. To Dr Joass; of Golspie, I must express the greatest obligation. He has aided me in every way, including the loan of important specimens, and furnished the greater part of the subjoined Bibliography. 2. Bibliography The following papers have been published on the subject, in chronological order as nearly as possible:— 1. Notes on the Sutherland Goldfield. By J. M. Joass, M.D. (with introduction by Sir R. I. Murchison). Quart. Journ. Geol. Socy. 1869. 2. Researches in British Mineralogy, By David Forbes, F.R.S., &c. Phil Mag. 1869. (One of a series, 1867-9, on allied subjects.) 3. Something from the Gold Diggings in Sutherland. By the Author of “Frost and Fire.” Odds and Ends Series, No. 22. 1869. 4. The Sutherland Goldfields. By Wm. Cameron. Glasgow Geol. Socy. 1870. 5. On the Matrix of the Gold in the Scottish Goldfields. By James Bryce, M.D., F.G.S. Brit. Assn. Beport. 1870. 6. The Geognosy and Mineralogy of Scotland. Sutherland. Part VI., p. 504. By M. Forster Heddle, F.RS.E. 7. The Geology of Sutherland. By H. M. 2. Bibliography

On the Cutting of Polarising Prisms 1

THE author showed the manner of cutting two new polarising prisms, designed by Ahrens and by himself, and described and figured in the Phil Mag. for June 1886. The Ahrens polariser is a rectangular parallelopipedon of calc-spar having square end-faces, and having its long sides in the proportion of about 1.6: 1 relatively to the short sides. The square end-faces are principal planes of section of the crystal. Two oblique sections are cut in the prism, being carried through the top and bottom edges of one end-face, and meeting in the horizontal middle line of the others. The dihedral angle between these planes of section is about 32°. The faces are polished and reunited with Canada balsam in the usual way. The advantages claimed for the new prism are: (1) decrease in length, (2) increase in angular aperture, (3) saving of light consequent on non-obliquity of end-faces, (4) minimum of distortion, (5) less spar required than in Hartnack, Glan, or Thompson prisms of same section. Against this are the slight disadvantages of (1) the line of section across end-face, and (2) the use of more spar than a Nicol of equal section. But Mr. Ahrens has recently added a thin covering-glass at the end-face crossed by the line of section, thereby making this line almost imperceptible; and he has also succeeded in finding a new method of cutting the prism in which there is extremely little waste of spar. The other prism designed by the author is a simple modification of the Nicol, giving a wider angle of field. A wedge is cut off each end of the calc crystal so as to make the new end-faces almost co-planar with a principal plane of section, and the crystal is cut through along the other diagonal of the sides. The results may be tabulated thus:—