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analysis. If wo take Canterbiiry "Water "Works water or the 

 Nailbourno water as samples of our best waters, we must not 

 call all waters which do not como up to this standard unwhole- 

 some, for there are many wells about which do not give quite so 

 good an analysis, but are perfectly wholesome, As a general 

 rule, all waters in this district containing much more free am- 

 monia, albuminoid ammonia, andclilorine than our standards may 

 safely bejudged tobo contaminated with sewage and if the albumi- 

 noidtigure is very high it shows tliat the pollution is still going on. 

 A nornud quantity of chlorine, with a very high albuminoid am- 

 monia figure, shows that the contamination is vegetable. The 

 albuminoid ammonia is tlic ammonia which organic matter gives off 

 when treated with suitable agents in the analysis ; the quantity 

 multiplied by 10 gives the amount of organic matter. High chlo- 

 rine, tVee ammonia and nitric acid figures, together with nitrites, 

 show that the water either has formerly been contaminated with 

 sewage or that there is some source of pollution not far off", but at 

 present the earth is capable of oxidising or rendering harmless the 

 organic matter. It is dangerous to drink tbis water, for no one can 

 tell how soon the earth may become overcharged with tlie filth and 

 lose tlie power of rendering it harmless. This water may possibly 

 be the means of communicating disease from a distance Waters, 

 which at one time give a good analysis, may be quite unfit for drink- 

 ing at anotlier. In connection with the subject of Nailbourncs, I 

 have brought two specimens of stone, which were kindly given me 

 by Mr. ShepparJ, who also gave me their liistory. First, a piece of 

 Travertine used by Archbishop Lanfranc in 1080 to fill up the 

 vaults of the groining of the nave of Canterbury Cathedral, being 

 stronger than chalk to resist compression and much lighter. That 

 nave fell down in 1400. In Herefordshire all the river valleys 

 abound in Tavertine, and nearly all the early churches are built of 

 it. In Kent, it is found at Postling, and in the valley between 

 Ewell and Alkham, and as a general rule at the fountain-head 

 of springs in limestone districts. The specimen originally came 

 from Alkham. Stalagmite was used at the building of the 

 choir of Canterbury Cathedral about 1100 to 1130. It was 

 used by Prior Ernulph and Prior Conrad who succeeded one 

 another. The space round the Communion Table in the 

 Cathedral is paved with it, and some of the outer columns are 

 made of it. When Prior Ernulph was made Bishop of 

 Eochester about 1115, he esteemed this stone so highlj^ that he 

 took two small columns with him, which are still to be seen in 

 the remains of the cloisters in the Dean's garden. He also gave 

 two columns to the Abbot of Saint Augustine's ; they are broken 

 up, but are still to be found built into the garden walls. 



