336 the president's address. 



ignis fatuus, a glimmering vision that eludes or deceives the 

 senses, and history is full of such experiences in all departments 

 of the province of thought. 



But I must not forget microscopy. So let me take you back 

 to my early days of its study, when, in summer evenings, 

 my favourite walk was across Primrose Hill by Belsize, 

 through green fields, over country stiles, up to the western 

 slope of Hampstead. Then we come to Shepherd's Well, a 

 spring of repute for the purity of its water, and water carriers 

 are moving to it and from it, illustrating the mode of supply 

 once in vogue in the City of London. It is engraved in Hone's 

 " Every Day Book," and is the source of the Tye-bourne, a 

 stream which has a history, receiving its prefix from the bifur- 

 cation of its outpour into the Thames which formed the Isle of 

 Thorney, where stand our Houses of Parliament and the ven- 

 erable Abbey of Westminster — a spot from its associations the 

 most sacred in our annals. As early as the 13th century its waters 

 were sought for by the citizens, and collected in conduits in Ox- 

 ford Street, near Stratford Place, by which was a banqueting- 

 house for the mayor and aldermen who, coming to inspect them, 

 regaled themselves in true city fashion. I have told the history 

 of this brook in another place ; my former pleasant walk through 

 green fields has passed into the usual uninteresting assemblages 

 of suburban dwellings and the spring into a sewer. 



At Shepherd's Well I made a gathering of minute algae, the 

 microscopic examination of which gave me a delightful spec- 

 tacle. It seemed as if I had before me chains of gold and 

 emerald gems, so looked the Diatomaceae and Desmidea?, and I 

 thought of the old Greek lyric who begins his ode by telling 

 us " That water is the best thing,"* whether, if he had seen what 

 I did, he might not have imagined it was the jewel case of the 

 goddess Nymph of the spring. Such would have been in 

 accord with the beautiful mythology of his day. Then, seeing 

 for the first time conjugation of the Spirogyra from beginning 

 to end, I had a lesson on the mystery of life. Nor was this all 

 by a long way, that I learnt from the water of Shepherd's Well, 

 and, as a young microscopist it spurred me on to the examina- 

 tion of the pools on the heath. 



Thus the ominous name of Tyburn may have a better memory 



* Pindar, Olympia Ode, " "Apisrov ^v v$wp." 



