trats'saCtioNs op section b* 



695 



Upper readies of the Wharf, Wanning, Ribhle, Aire, and Calder t\'111 le sufficiently 

 illustrative : — 



Barden 



Grimwith Beck 

 Gate-up-Gill 

 Bleabeck 

 Buckden Pike 

 Starbottom . 

 Kettlewell . 

 Buckden Village 

 Gaping Ghyll 

 Beck Head, Clapdale 



Chlorine 

 parts per 

 100,000 



1-0 



1-2 



0'7 



10 



1-0 



0-8 



1-0 



1-2 



1-2 



1-3 



As the sea is approached, and more populous districts are reached, the chlorine 

 rises, and remarkable examples of rise may be met with on the same hill slope. 

 Halifax furnishes a striking instance. The town rests on a sloping bed of Mill- 

 stone grit, the ancient and most thickly populated part being towards the bottom 

 of the incline. The ground waters of the highest parts — Mount Tabor — vary from 

 1'6 to 2'6 ; widely separated wells, about halfway down, yield the figure 3'8 ; 

 while towards the bottom of the slope two wells give the figures 4*7 and 55. The 

 public water supply from Pennine gathering grounds, ten miles away, stands at I'S. 



The figures obtained for other parts of the West Riding have not yet been 

 severely collated, and are therefore reserved for a further communication. 



4. 0)1 a limiting Standard of Acidity for Moorland Waters. 

 By William Ackroyd, F.I.C, Public Analyst for Halifax. 



Many large towns, more especially in the West Riding of Yorkshire, have their 

 public water supplies of moorland origin. The case of Milnes v. the Hudders- 

 tield Corporation in 1881 gave great prominence to the fact that this class of water 

 may give rise to plumbism. No satisfactory explanation could be given at the 

 time, and it iw only during the present decade that it has been clearly understood 

 that the plumbo-solvent action of moorland waters is to be associated with acidity. 

 An idea of the relation is furnished by the following determinations : — 



Parts per lOO'OOO. 



Acidity in Equivalent Lead dissolved from 



of Sulphuric Acid. A-iuch Piping, 



1. . . . 0-20 In 1 hour ' 



2. . . , 030 „ ... 



3. . . . 0-29 „ ... 



4. . . . 1-34 



5. . . . 1-59 



In J hour 



03 



0.57 



025 



71 



95 



The acidity is due to carbonic anhydride and peaty acids, and the total is found 

 hy ascertaining the number of c.c. of N/100 alkali required to neutralise 100 c.c. 

 of the water, the result being expressed as sulphuric acid. Pheuolphthalein is 

 used as the indicator. 



The acidity may be very high as from peaty gathering grounds of small incline, 

 say 1 in 44, or comparatively low in gathering grounds of steep incline, sav 

 1 in 12.' 



In the former case violent action on lead precludes its use for domestic con- 

 sumption, and in the latter even a limit must be placed on the degree of acidity 

 allowable. During epidemics of plumbism in the West Riding much diversity of 

 opinion has been expressed on vaiious points connected with the matter which the 



Ackroyd, Journ. Chcm. Sec, 1S09, p. 199. 



