INTRODUCTION. xlv 



ceed best in the wider spaces, where they may have the 

 means of extending their stems in all directions. Water 

 may easily be introduced into rockwork by means of 

 lead or copper pipes being brought to the surface through 

 the mass ; and a small perforation made at desirable or 

 necessary points at the highest elevations will amply 

 provide for the complete irrigation of the mass, wherever 

 and whenever it is wanted. The pipes should be fur- 

 nished with a cock or valve at some conveniently 

 approachable point, for the purpose of regulating and 

 thoroughly controlling the supply at all times. These 

 simple directions will enable those who desire a little 

 rockery to construct it on good principles. Extensive 

 rockworks or rock-gardens will always be rare on account 

 of their cost ; for under the most favourable circum- 

 stances, the materials and the labour necessary to their 

 construction are among the most expensive that are re- 

 quired in any form of garden engineering, and those con- 

 templating anything grand in this way will choose more 

 comprehensive guides on the subject than this little work 

 professes to be. It should be stated, before leaving this 

 matter, that the smaller the rockwork in area of base, 

 the more humble should be its elevation. Not only is 

 any attempt at undue prominence not beautiful, but it 

 is likely to frustrate the object for which any rockwork 

 is designed — namely, the successful culture of alpine or 

 rock plants. High and narrow erections of the kind are 

 more liable to suffer from drought than those whose base 

 stands in better proportion to the elevation ; they are, in 

 fact, more liable to every alternation of heat, cold, and 

 drought — and that of all things is to be avoided as much 

 as possible in the management of alpine plants. They 



