April 22, 1922] 



NATURE 



533 



Calendar of Industrial Pioneers. 



April 20, 1821. Franz Karl Achard died. — De- 

 scended from a French protestant family, Achard 

 was born in Berlin, worked at chemistry with Marg- 

 graf and became director of the physical department 

 of the Berlin Academy of Sciences. He was a pioneer 

 in the production of sugar from beetroot and in 1801 

 erected a sugar factory. 



April 21, 1819. Oliver Evans died. — Bom in 

 Newport, Delaware, in 1755, Evans became a practical 

 miller. He was the author of numerous improve- 

 ments in milling, and his system was adopted both 

 in America and Europe. He also experimented with 

 liigh-pressure steam ; in 1803 he began building steam 

 engines, and the same year constructed a self-propelling 

 dredging machine. 



April 21, 1889. Robert Stirling Newall died. — 

 The inventor in 1840 of iron wire ropes, Newall 

 established works at Gateshead and became famous 

 as a maker of submarine telegraph cables. The first 

 successful cable between Dover and Calais was 

 made by him in 1851, and he constructed half of the 

 first Atlantic cable. He was also known as an 

 astronomer, and presented one of his large telescopes 

 to the University of Cambridge. 



April 22, 1833. Richard Trevithick died. — One of 

 the greatest engineers and the most fertile inventors 

 of his day, Trevithick, like Evans, turned his attention 

 to the use of high-pressure steam, constructed double- 

 acting high-pressure engines, and between 1797 and 

 1808 made important experiments with locomotives. 

 The son of a manager of a mine, Trevithick became 

 chief engineer of some of the mines in Cornwall. 

 In 1 81 3 he erected some of his engines in Peru, where 

 he resided about ten years. 

 ^ April 22, 1864. Joseph Gilbert Totten died.— 



\ Trained as a military engineer at the West Point 

 Academy, Totten rose to be colonel of the Corps 

 of Engineers of the United States, and became known 

 for his researches on the strength of materials and 

 allied subjects, his work on the Ughthouse board, 

 and his investigation of New York harbour. 



April 23, 1897. Adam Hilger died. — The founder 

 of a firm of scientific instrument makers, Hilger was 

 a native of Darmstadt. After being trained as a 

 mechanical engineer he worked under Ertel in Munich 

 and under Lerebours in Paris and about 1870 came 

 to England. A few years later he set up in business 

 for himself at Islington, becoming well known as a 

 constructor of instruments for celestial spectroscopy. 



April 25, 1840. Sir Robert Seppings died. — Master 

 Shipwright at Chatham Dockyard, and then from 

 1813 to 1832 Surveyor of the Navy, Seppings intro- 

 duced improved methods of docking and undocking 

 ships, and was the inventor of the system of diagonally 

 bracing and trussing the frame timbers of ships, an 

 innovation of the first importance. He gave an 

 account of his improvements to the Royal Society 

 and was awarded the Copley medal. 



April 26, 1893. Edward Alfred Cowper died. — An 

 apprentice of John Braithwaite, Cowper afterwards 

 worked with Fox and Henderson, and was employed 

 on the buildings for the Great Exhibition of 1851. 

 He then became a consulting engineer and was 

 known for his work in connection with the develop- 

 ment of the compound steam engine, his invention 

 of the regenerative hot blast stove, and the intro- 

 duction in 1868 of the modem bicycle wheel with 

 wire -spoke suspension. In 1880 he was elected 

 President of the Institution of Mechanical Engineers. 



E. C. S. 



NO. 2738, VOL. 109] 



Societies and Academies. 



London. 



Royal Society, April 6. — Sir Charles Sherrington, 

 president, in the chair. — F. E. Smith : On an electro- 

 magnetic method for the measurement of the hori- 

 zontal intensity of the earth's magnetic field. A 

 Helmholtz-Gaugain arrangement of coils consisting 

 of two interwoven helices of bare copper wire wound 

 in spiral grooves in a marble cylinder are mounted 

 on each side of the centre. Each coil is of 30 cm. 

 radius, of six turns, and of i§ mm. pitch. The 

 cylinder is mounted on a non-magnetic base, and 

 can be rotated about a vertical axis. The magnet 

 at the centre is i cm. long and about 6 sq. mm. in 

 cross-section ; it is supported on a V of aluminium 

 foil by a fine quartz fibre, to which is attached a 

 reflecting mirror and a damping vane. The magnet 

 is easily removed from its support, and a copper 

 wire of equal weight substituted. The axial magnetic 

 field due to the current in the coils is made slightly 

 greater than " H," and its component in the magnetic 

 meridian opposes H. By adjustment of the angle 

 a between the axis of the cylinder and the direction 

 of magnetic north, the indicator magnet is caused to 

 set at right angles to the meridian. When torsion 

 is eliminated, H =Fi cos a, where F is constant of 

 coil system and i is current. A determination of H 

 occupies less than 4 minutes. The probable error. 

 Including that due to uncertainty of the value of the 

 current, measured by a current balance, is about 

 + 4 in 100,000. — G. I. Taylor: Stability of a viscous 

 liquid contained between two rotating cylinders. 

 Steady motion of viscous liquid between two con- 

 centric rotating cylinders is unstable for symmetrical 

 disturbances, provided the velocity of the system 

 is greater than a certain value, and the ratio of angular 

 velocities of the cylinders is less than the reciprocal 

 of the square of the ratio of their radii, or is negative. 

 The type of instability is periodic along the length 

 of the cylinders, consisting of vortices enclosed in 

 partitions rectangular in section, and they rotate 

 alternately in opposite directions. When the cylinders 

 rotate in the same direction each vortex extends 

 across the space between the cylinders. The length 

 occupied by each vortex is equal to the thickness 

 of fluid between them. Wlien the cylinders rotate 

 in opposite directions, two systems of vortices 

 rotating as though geared together appear. Some 

 criteria for stability in approximate form suitable 

 for numerical computation have been obtained. — 

 T. H. Havelock : Dispersion formulae and the 

 polarisation of scattered light ; with application to 

 hydrogen. Simple types of dispersion formula? are 

 considered when the medium consists of anisotropic 

 molecules distributed at random and having an axis 

 of symmetry. A formula for the corresponding 

 ratio of the intensities of the two polarised components 

 of light scattered at right angles, when the primary 

 light is unpolarised, is given. The case of hydrogen 

 is examined numerically and the ratio of the intensities 

 agrees substantially with Lord Rayleigh's experi- 

 mental value. — G. R. Goldsbrough : The cause of 

 Encke's division in Saturn's ring. A satellite will, 

 from its inclined path alone, produce one new division 

 in the ring system. If the satellite be Mimas, a 

 narrow division closely corresponding to Encke's 

 division is produced. Similarly, Enceladus should 

 produce a division in Ring B, but it would be almost 

 unobservable. — C. Spearman : Correlation between 

 arrays in a table of correlations. Correlations be- 

 tween arrays are expressed as functions of the 

 independent variable elements entering into the 

 main variables. When only one element is common 



