Henry Dresser and Victorian Ornithology: Birds,Books and Business

The metaphysical commitment to the circle as the essential element in the analysis of celestial motion has long been recognized as the hallmark of classical astronomy. Part I of this paper contains a discussion of how, for Kepler, the circle also functions in geometry to select the basic polygons, in music to select the basic harmonies, and in astrology to select the basic aspects. In Part II, the discussion centres on the question of how the replacement of circular planetary orbits by elliptical orbits in the Astronomia Nova of 1609 affected Kepler's metaphysical commitment to celestial circularity that was made manifest in the derivation of planetary radii in the Mysterium Cosmographicum of 1596. The answer is found in the new and much more accurate derivation of both the planetary radii and their eccentricities in the Harmonice Mundi of 1619. It is the relationship of the diurnal movements of single planets at aphelion and perihelion to specific musical consonances that provides the first step. Then, in the second step, these ratios are ‘tempered’ so that all six planets can provide a heavenly choir. The third and final step employs the ‘mean period’, which is obtained directly from the tempered ratios given by musical theory and diurnal (not annual) motion, in the 3/2 power law to calculate the planetary radii and eccentricities with amazing accuracy. Thus the ellipse is necessary to supply the variation in angular velocities that contain the Creator's archetypal celestial circularity.     

Walls of resonance: Institutional history and the buildings of the University of Manchester

The built environments of universities are useful for telling stories about their development. Exteriors – walls, windows, doorways, the relative positioning of different facilities – are particularly suited to broad institutional narratives: the rise and decline of scientific disciplines, for instance, or the institution’s changing relationship with benefactors and the wider public. Exteriors are also conveniently accessible to public audiences.This paper explores the possibilities through the case of the University of Manchester. The approach is in a sense the converse of industrial archaeology, which seeks to understand the functioning of a site from what survives of its material form: here, we have begun with knowledge gained largely from document sources, and aim to bring it to life for visitors by pointing to the material consequences. Connecting doors and architectural symmetries illustrate founding unifications and alliances; infilling and glassing-over, constrained expansion; grand but obscured frontages, displaced priorities.Populating the site with accounts of its lived existence is a powerful tool to communicate history, but it is important not to create an ‘official’ memorialisation: audiences often know the site at first hand, and may question any received version. I conclude by calling for a reflexive treatment, mapping the histories of the stories themselves.     

无源数据传输系统的改进型Manchester码

针对能量传输效率和位定时信息提取的要求,提出了一种基带码型即改进型Manchester码。文中给出了该码的编码方法,分析能量传输效率、功率谱及AWGN信道非相干解调的误码性能,提出了解码方法并实测出系统关键节点的电压波形。该编码的能量传输效率比Manchester码高55%,同时具备位定时信息易于提取的优点,可以在非相干解调中充分利用其位定时信息解决接收端内部震荡器不稳定造成的采样时刻误差累积问题。     

W. T. Astbury,Rosie Franklin,and DNA: A memoir

Astbury's role in the X-ray study of DNA; his failure to continue his pioneering appraisal; surprising details of his MRC grant application; and his disinterest in Beighton's DNA photographs demand attention. Rosie Franklin's later involvement and behaviour receive comments, which, as with Astbury, are based on personal knowledge.