The photographic experiments of Henry Brougham

Abstract

Of all the British claimants to the invention of photography, Henry Brougham is the one whose experiments have been given least attention in existing histories of photography. In his posthumously published three-volume autobiography of 1871, The Life and Times of Henry, Lord Brougham, written by himself, Brougham claimed to have engaged in some ‘experiments upon light and colours’ during the years 1794-–5 (when he was 16 years of age). He had, he tells us, included a discussion of his experiments in a paper offered to the Royal Society in 1795. Most of this paper, his first in the field of natural philosophy, was published in the Society's Philosophical Transactions (No. 86) of 1796 under the title ‘Experiments and observations on the inflection, reflection, and colours of light’. The paper, as published, was an attempt to discover analogous relationships between the bending of light within bodies (refraction or, using the 18th-century term, ‘refrangibility’) and the bending of light outside of bodies (reflection and diffraction or, in Brougham's terminology, flexion). As he wrote in the opening lines of his paper:

It has always appeared wonderful to me, since nature seems to delight in those close analogies which enable her to preserve simplicity and even uniformity in variety, that there should be no dispositions in the parts of light, with respect to inflection and reflection, analogous or similar to their different refrangibility. In order to ascertain the existence of such properties, I began a course of experiments and observations, a short account of which forms the substance of this paper.¹     

The Employment of Reason

Rationalism in the Netherlands is characterised by pragmatism. As Charles Rattray explains it is a practical bent that was driven in the 20th century by the exigencies of building cheaply and quickly a large amount of social housing on a relatively small amount of land. It is a strand that has been underscored by a belief in reason across time and a confidence in an analytical approach. Copyright © 2007 John Wiley & Sons, Ltd.     

Orbit systematics in anisotropic Kepler problem

We revisit the Anisotropic Kepler Problem (AKP), which concerns with trajectories of an electron with anisotropic mass term in a Coulomb field. This is one of the most fundamental fields in Quantum Chaos. Nowadays various quantum systems are challenging us. Classical theories of these may have chaos. Quantum mechanics have developed from integrable cases and may have to be reformulated for such cases. AKP then serves as a suitable testing ground for quantum chaos. We first review a pioneering work by Martin Gutzwiller (J Math Phys (1977) 18:106). We shall show the systematics of the trajectories using ample figures from an extensive numerical analysis. Then we focus on the rolê of hyperbolic singularities and we comment on the approximations in an analytic formulation. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

几何代数及其在摄动Kepler问题中的应用

为避免卫星轨道摄动分析过程中多种代数系统繁琐的相互转换,创新性地引入几何代数系统,在统一的代数框架内研究摄动开普勒问题.利用几何代数体系中的位置空间与旋量空间之间的转换关系,将摄动Kep ler方程转化为线性、正则的旋量方程(简称KS方程),并给出Kep ler旋量方程的解.最后,通过与传统方法比较,说明几何代数这种新工具在卫星轨道运动中应用的独特优势.     

Weaverbird: Topological Mesh Editing for Architects

Design and computation consultant Giulio Piacentino is the developer of WeaverBird. Here he describes how the plug-in ‘gives architects more geometric control and allows them to create complex surface structures that join in orderly ways, yet in arbitrary configurations’.     

All Night Long: The Architectural Jazz of the Texas Rangers

In the mid-1950s, a group of young faculty at the University of Texas School of Architecture in Austin - aka the Texas Rangers - entertained themselves with weekly sessions of a sophisticated, collective drawing game, ‘Dot-the-Dot’, in which there was an emphasis on inventive fluency in hand drawing as well as an innate knowledge of historic European city plans. What happened when Mark Morris , Visiting Associate Professor at Cornell University, decided in a design studio to ask present-day students to revive the game?     

开普勒运动的“不变性”

从开普勒三定律出发,分析这类运动中的守恒量。论证三定律,并分析定律内容的内涵,提出角动量守恒、机械能守恒,隆格-楞茨矢量守恒,并由三定律出发推导万有引力的二次方反比规律,结合牛顿第二定律,证明了万有引力定律。     

Poland: transforming factories into cultural and educational facilities

Architecture has an important role to play in the refurbishment and renovation of existing building stock, often leading to the wholesale regeneration of run-down and derelict areas. Hubert Trammer looks at how the redevelopment of five disused industrial sites in Poland has been driven by the need for new educational and cultural facilities and the widespread availability of abandoned manufacturing bases. Copyright © 2006 John Wiley & Sons, Ltd.     

A Note on the Kepler Problem

J. Moser proved that the flow arising in the Kepler problem and restricted to the manifold of the constant energy E < 0 is equivalent to the geodesic flow on a sphere. This was proved by means of some algebraic manipulations with the Hamilton function. In a similar way Yu. S. Osipov proved that this flow is equivalent to the geodesic flow on the Euclidean space for E = 0 and on the Lobachevskii space for E < 0. In this paper results of such kind are related to the approach to the Kepler problem suggested by Hamilton (this approach seems to be the simplest one). For the planar Kepler problem one first considers the picture arising on the hodograph plane, where the hodograph curves turn out to be circles or arcs of circles. For fixed E one obtains a net (2-parameter linear system) of circles which in the case of E < 0 can be obtained from the system of great circles on a sphere by a stereographic projection; related geometric construction exists also for other E. This leads in a geometrical way to Moser's result. Moser showed also that for E < 0 the trajectory space of the covering flow on the universal covering space (which is a three-dimensional sphere ³) is a two-dimensional sphere ²; the corresponding map ^{3 2} is the Hopf fibration. An additional remark made below is that under appropriate normalizations and modifications this is the map