k 



WATER. 13 



being taken, whatever arrangement "be chosen, that 

 the masses stand with stability. It is of little 

 consequence what sort of rock is selected, — lime- 

 stone, sandstone, granite, conglomerate, — but the 

 rougher, and the more full of cavities and angles, 

 the blocks are, the better will be the effect. 



Water. — The purity of the water is of great 

 importance. In London, sea-water may be easily 

 obtained, by giving a trifling fee to the master or 

 steward of any of the steamers that ply beyond 

 the mouth of the Thames, charging him to dip it 

 in the clear open sea, beyond the reach of rivers. 

 I have been in the habit of having a twenty 

 gallon cask filled for me, for which I give a couple 

 of shillings. 



The vessel in which it is conveyed requires 

 attention. A cask is the best, if a considerable 

 quantity of water is required ; but it is absolutely 

 indispensable either that it should be new, or at 

 least that nothing injurious should have been 

 previously contained in it, such as spirits, wine, 

 chemicals, acids, &c. ; since no soaking will prevent 

 hurtful qualities from being communicated to the 

 water. Even the bungs ought to be new. I knew 

 an instance in which a consignment of animals 

 was lost, from no traceable cause, except that the 

 water- cask, which was quite new, had been stopped 

 with a bung, which had been previously used in 

 a jar of some chemical solution ; yet the bung had 

 been, as was supposed, thoroughly soaked and 

 cleansed. If a cask of fir- wood can be procured, it 

 is preferable : the wood of the oak, of which wine- 

 casks are usually made, gives out tannin or gallic 

 acid, to the contained water, which by its astrin- 

 gency converts the animal integuments into leather* 



