On 6 September 1836, George White wrote from Hatton Garden to T. B. Hall in Liverpool:

I see by an advertisement that [there is] a proposition to form a Society to be called the Botanical Society of London—Its objects are the advancement of Botanical Science in general but more especially systematic and descriptive Botany—the formation of a Library, Museum & Herbarium—A meeting will be held at the Crown & Anchor, Strand, tomorrow evening & it is my intention to attend it—It has been proposed that Ladies should be admitted!!!

If the writer of those words lived up to his declared intention and did attend that or any other of the long string of inaugural meetings the Society held during the last quarter of that year, he would have been startled, perhaps even appalled to find how seriously that last-mentioned proposal had been taken. For on 3 November he would have found in the room at the Crown and Anchor Tavern (according to one report) ‘a crowded assembly of both ladies and gentlemen’. He would also have heard the founder of the Society, the nineteen-year-old Daniel Cooper, deliver a paper on the effects of light on plants, which (according to the same report) ‘excited great interest, more particularly with the ladies’. A fortnight later the meeting was again ‘numerously attended’ and again it attracted a number of the supposedly unlearned sex, some of whom by then were ‘members of the society’ unambiguously.

In June 1849 William Thomson (Later Lord Kelvin) wrote to Michael Faraday suggesting that the concept of a uniform magnetic field could be used to predict the motions of small magnetic and diamagnetic bodies. In his letter Thomson showed how Faraday's lines of magnetic force could represent the effect of the ‘conducting power’ for magnetic force of matter in the region of magnets. This was Thomson's extension to magnetism of an analogy between the mathematical descriptions of the distribution of static electricity and of the diffusion of heat through uniform bodies. In 1850 Faraday published his first comprehensive theory of the magnetic properties of matter. He explained the behaviour of matter in the field by four assumptions: that matter has a specific disturbing effect on the normal distribution of lines of magnetic force; that this effect depends on its ability to conduct or transmit the magnetic action; and that material bodies tend to move so as to cause the least possible disturbance of the lines from their normal distribution. Faraday also assumed that diamagnetics transmit magnetic action less well than empty space, while paramagnetics transmit it more readily than space. This implied that space must have a specific conductivity between that of paramagnetic and diamagnetic materials. In order to preserve a distinction between matter and space Faraday defined ‘matter’ as either the source of action or as a conductor which is able to influence the lines of action; space was the absence of such powers. While space could conduct, it differed from matter in that it could neither originale lines of force nor influence their course and distribution.

In 1826 André-Marie Ampère published the ‘Mathematical theory of electrodynamic phenomena, uniquely derived from experiment’, in which he showed how the mathematical law for the force between current elements could be derived from four ingenious equilibrium experiments. He made a great show of following a Newtonian inductivist methodology, and his law, like Newton's for gravitation, was presented as a purely descriptive mathematical expression for a certain class of phenomena, one for which its author did not provide any causal or ontological justification. Ampère's electrodynamics would accordingly seem to have been a solid contribution to the Laplacian-Newtonian approach to physics so actively pursued in France during the first quarter of the nineteenth century. It does not surprise us to read that his electrodynamic force law and his molecular-currents theory of magnetism were immediately and widely accepted by his French contemporaries. Ampère was, in this view, just another of the many great French mathematical physicists of the period.