Oil (he Alps of Dauphiiic. IG") 



4. Water, v.hich contains less than about an OOOOtli of salts in 

 solution, cannot be safely conducted in lead-pipes, without certain 

 px'ecautions, 



5. Even this proportion will prove insufficient to prevent corro- 

 sion, unless a considerable part of the saline matter consist of carbo- 

 nates and sulphates, especially the former. 



6. So large a proportion as a 4000th, probably even a consider- 

 ably larger proportion, will be insufficient, if the salts in solution be 

 in a great measure muriates. 



7. In all cases, even though the composition of the water seems 

 to bring it within the conditions of safety, now stated, an attentive 

 exainination should be made of the water, after it has been running 

 for a few days through the pipes. For it is not improbable, that 

 other circumstances, besides those hitherto ascertained, may modify 

 the preventive influence of the neutral salts. 



8. When the water is judged to be of a kind which is likely to 

 attack lead-pipes, or when it actually flows through them impreg- 

 nated with lead, a remedy may be found, either in leaving the pipes 

 full of the water, and at rest for tliree or four months, or by substi- 

 tuting for the water a weak solution of phosphate of soda, in tho 

 proportion of about a 25,000th part. 



February 22. — The Right Hon. Lord Greenock, V. P., in 

 the Chair. 



I. On the Necessity of the Sense of Muscular Action to the 

 full Exercise of the Organs of the Senses. By Sir 

 Charles Bell, K.H. 



March 7.— Sir T. M. Biiisb.vne, Bart., President, in the 

 Chair. 



1. On the most recent Disturbance of the Crust of the Earth, 



in respect to its suggesting a Hypothesis to account for 

 the Origin of Glaciers, By Sir George Mackenzie, Bart. 

 (Published in this Journal, vol. xxxiii. p. 1.) 



2. Geological Notes on the Alps of Dauphine. By Professor 



Forbes. 

 The district proposed to be described, in so far as it was studied 

 by the author in two journeys in 1839 and 184J, is an out-Iyer or 



