t 
EUCALYPTUS TREES. 615 
turn these acquisitions to an enlightened account for 
whole communities. 
It is unquestionably of importance to provide in 
_any scientific garden, from time to time, accurate cata- 
ca 
logues of the contents, quite as much as an inventory 
as to guide information and to regulate interchanges. 
But this is a work of such magnitude and constantly 
recurrent additional labor that even the grand estab- 
lishment of Kew has shrunk from the task of issuing 
-an index of all its plants since a long series of years. 
Not only the difficulty is encountered to identify the 
plants with specific accuracy, for which purpose they 
must be examined while in flower and fruit; but, 
moreover, such catalogues become almost instantly 
incomplete or altered, partly because annuals are a 
very uncertain possession, partly because we cannot 
 - imitate all the conditions under which so many plants 
of the alps, the moors, the heaths, the saline steppes, 
or the tropical jungles, are naturally thriving ; hence 
a number of species, capricious in their mode of 
growth, are apt to perish in culture, however much 
care may be bestowed on them. Then, again, daily 
new aceess is gained in any great horticultural collec- 
tion, while in the process of discovery some changes 
will continually occur in the nomenclature, until all 
_ plants of the globe shall have been fully collected and 
- exhaustively studied. Under these circumstances of 
adversity I raised the question among leading directo- 
_ rial colleagues in Europe, whether, by united efforts, 
we could provide for the publication of an universal 
catalogue in annual editions, or at a regular interval 
of'a few years. It appeared to me that, just-as all 
navigators possess one nautival almanac, prepared 
