I think you would be amused if you were here now to see my lectures – in my elementary one I have got a front row entirely consisting of young women (some of them not so young neither, as someone says in Jeames' Diary) and they take notes in the most painstaking and praiseworthy fashion, but the most extraordinary thing is that I have got one at my advanced lecture. I am afraid she does not understand a word and my theory is that she is attending my lectures on the supposition that they are Divinity and she has not yet found out her mistake.

Professor J. J. Thomson to Mrs H. F. Reid, 4 November 1886

When Joseph John Thomson used this light-hearted description to brighten up a letter to a family friend, women had been attending physics lectures at the Cavendish Laboratory for four years. Though the picture was designed to amuse the recipient, a married woman, joviality thinly disguised unease. Thomson's previously homogeneous audience had been physically split into two opposing sections with young, male students at the back and older, female students along the front row. Intellectual divisions were also apparent; the women took notes in a different, non-male way, and without the sharpness of a masculine mind they could not understand the content. The message was plain – the women had made a mistake. Their infiltration had been unsuccessful and they did not fit in.