Known as the Gold Baron, John Ewing (1844-1922) pioneered the use of deep hydraulic elevators and large scale hydraulic sluicing at the St Bathans goldfield and elsewhere in Central Otago. His career consisted in dramatic successes and ruinous failures. Drawing on recent philosophical work on the nature of luck, we consider the role luck played in Ewing's various gold mining endeavors.

The first steam powered bucket ladder gold dredge anywhere in the world appeared in Otago, New Zealand, in 1881. Adding paddock (land) dredging in 1889 and the tailings elevator in 1894 completed what became known as “The New Zealand Gold Dredge”. Its productivity and efficiency initiated a new type of mining worldwide. Burt justifiably classed it as one of seven major innovations that transformed mining from a manual small-scale craft into a bulk mechanised industry. This paper reviews the diffusion of this transformational technology from Otago into its new international world. First, the dissemination of Otago dredge developments, by international mail, newspapers, and telegraphy, sparked overseas interest and technical visits. A Dunedin dredge design engineer headhunted to San Francisco followed in 1896 and revolutionised gold dredging there. Representing physical diffusion, exports of dredge components, initially to Australia and Siberia, commenced from Dunedin workshops in 1899. One workshop established a partnership in Melbourne. Otago construction crews built the exported dredges overseas, thus effecting intellectual (human) diffusion. New Zealand dredge masters and crew working on foreign-built dredges continued the technology transfer longer term. Two Dunedin dredge designers also moved their consultancies to London and dominated dredge design for the extensive Southeast Asian tin fields. By 1910, Otago gold dredge technology had reached North America, Australia, Siberia, British Columbia, the Philippines, South America, Southeast Asia, Serbia, and West Africa. This remarkable “diaspora” is attributed to the effectiveness of the Otago technology and the expertise at all levels of its gold dredging community.

In the collections of the National Library of Colombia lies a document, signed in 1790, by the renowned physician Sebastián López Ruiz, regarding his explorations of mercury in the isthmus of Panama. In it, he documents testimonies from neighbors of both sexes, young and old, about findings and outbreaks of mercury in different places; secret extractions, sightings of the metallic substance in cities, nearby and distant marshes; both in ravines and hillsides, as well as in streams near the sea. The purpose of this work is to critically read this document, and the others attached in the file containing it, in order to elucidate the veracity or not of its statements, sometimes surprising, and the reasons that could have led to its writing. In doing so, we will be able to better understand the social place of science in the enlightened context of the New Kingdom of Granada, and the role of honor and nobility as incentives, not only for scientific research of natural resources during the Enlightenment, but also as promoters of scientific deceit.

During the intense debates between fixism and mobilism, Chinese geologist J.S. Lee published the paper The Fundamental Cause of Evolution of the Earth’s Surface Features” in 1926 in the Bulletin of the Geological Society of China, supporting mobilism. He attributed continental movements to the variations of the Earth’s rotation speed: when the rotation speed increases, it generates forces that compel the continents and seawater to move horizontally from the poles toward the equator and vice versa. It was on this idea that his Geomechanics was established in the following decades. Lee was the most influential geologist in 20th-century China, and Geomechanics was China’s most prevalent geological theory, especially during the Cultural Revolution. In the early 1970s, Plate Tectonics theory was introduced into China, and the status of Geomechanics was replaced eventually. This paper provides a historical analysis of Lee’s initial conception of Geomechanics by introducing his first publication on geotectonics with annotated excerpts from it.