220 THE EAELY HISTOEY OF [CHAP. IV. 



matics ; nature of electric fluids, the atmosphere, air- 

 pump, spring and weight of the air proved by experi- 

 ments, barometer. The last lecture was given on 

 Saturday, 31, at eight. This was followed by other 

 courses, making altogether twenty lectures. 



After his return to Manchester Dalton wrote to his 

 brother, February 1, 1804 : 



DEAR BROTHER, I have the satisfaction to inform thee 

 that I returned safe from my London journey last seventh 

 day, having been absent six weeks. It has on many accounts 

 been an interesting vocation to me, though a very laborious 

 one. I went in a great measure unprepared, not knowing 

 the nature and manner of the lectures at the Institution 

 nor the apparatus. My first was on Thursday, December 22, 

 which was introductory, being entirely written, giving an 

 account of what was intended to be done ; and on natural 

 philosophy in general. All lectures were to be one hour 

 each, or as nearly as might be. The number attending were 

 from one to three hundred of both sexes, usually more than 

 half men. I was agreeably disappointed to find so 

 learned and attentive an audience, though many of them of 

 rank. It required great labour on my part to get acquainted 

 with the apparatus and to draw up the order of experiments 

 and repeat them in the intervals between the lectures, 

 though I had one pretty expert to assist me. We had the 

 good fortune, however, never to fail in any experiment, though 

 I was once so ill prepared as to beg the indulgence of the 

 audience as to part of the lecture, which they most hand- 

 somely and immediately granted me by a general plaudit. 

 The scientific part of the audience was wonderfully taken 

 with some of my original notions relative to heat, the gases 

 &c., some of which had not before been published. Had my 

 hearers been generally of the description I had apprehended, 

 the most interesting lectures I had to give would have 

 been the least relished ; but, as it happened, the expectation 





