16 ACTION OF LEAD IN DISTILLED AND RIVER WATER. 
ART. V.— ON THE ACTION OF LEAD IN DISTILLED AND 
RIVER WATER. 
BY RICHARD PHILLIPS, JUN. 
The author considers, from the action which is the sub- 
ject of his paper, the following points of interest to arise : 
1st, whether it is necessary that the lead should be ex- 
posed to the air, or whether the action would take place if 
it were below the surface of the water ; 2nd, whether pure 
or distilled water, deprived of all atmospheric air, has any 
action on lead ; 3rd, as to what is the nature of the white 
precipitate ; 4th, if, besides this white precipitate, any solu- 
ble salt of lead is found ; and 5th, as to which of the salts 
contained in river-water the non-formation of the white 
precipitate is due. 
He proceeds to notice the remarks of Dr. Christison and 
Colonel Yorke on these subjects, and then gives his own 
experiments. 
As to the first. In bottles containing distilled water 
were placed two pieces of lead of nearly equal size. In 
both a white precipitate occurred, but in that in which the 
lead had been exposed above the surface of the water, a 
far greater quantity than in the one where the lead had 
been covered with the water ; and he concludes from this 
experiment, that although it is not necessary that the lead 
should be exposed above the surface of the water for the 
action to take place, still by offering a passage to the gases 
contained in the atmosphere it accelerates it. 
The author observes, " I have before stated, Dr. Christi- 
son does not describe the method by which he performed 
his experiment on the non-solubility of lead in pure distil- 
led water ; and although I agree with him as to the fact, as 
I found some difficulty in ascertaining it, I will describe the 
process I followed. I found that on boiling pure distilled 
