˜Aœ Determination of the Solar Parallax and Mass of the Moon from Heliometer Observations of the Minor Planets Iris, Victoria and Sappho Made in the Years 1888 and 1889 at the Royal Observatory, Cape of Good Hope, in Co-operation with the Observatories of Yale College (Newhaven), Leipzig, Göttingen, Bamberg and Oxford (Radcliffe), and from Meridian Observations Made at All the Principal Observatories PDF Download