March i, 1887.J THE TROPICAL AGRICULTURIST- 



5S9 



by the raUi-gauge ; and we must rely on the known 

 habits of plants, in their relation to moisture of air 

 and soil, to help us iu this respect. Any one who 

 has passed quickly between Nice, Palermo, and 

 Algiers, cannot but have noticed the ilifferenee in 

 the general aspect of the vey;etation at each place ; 

 its greater activity at the latter station indicating a 

 greater amount of moisture in the air and soil than 

 at Nice, while PaJermo holds an intermediate position. 

 "The following observations' should be recorded of 

 each plant in the list. Does the plant or tree grow 

 at the station ':* Is it protected from the cold, sun, 

 or wind r" Does it blossom ? and at what date does the 

 first blossom appear? Do its fruit or seeds ripen and 

 at what dato do they arrive at maturity ? With respect 

 to the deciduous trees (Pomegranate, Vine, Fig, 

 Almonds, and Horse Ohestiiut), at what date do the 

 leaves open (first leaf -surface visible); ihe first blos- 

 soms open ; and the first fruit or seeds ripen ? 



(1) Carob or Locust-Bean 

 (Ceratonia Siliqua) 



Prickly Fear or .Indian 

 Fig (Oactas Opuntia) 



American Aloe (Agave 

 Americana) 



liamboo (Bambusa vul- 

 garis ?) 



Dwarf European Palm 

 (Ohatna'rops humilis) 



Oleander (Nerium Ole- 

 ander) 



Date Palin (Phoenix dac- (.1) Magnolia (M. Grandi- 

 tylifern ) flora) 



(2) Pomegranate (Punica Camellia (0. japonica) 

 Granatnm) Myrtle (Myrtus commu- 



Banana (Musa sapien- nis) 



turn) Vine (Vitis vinifera) 



Lemom tree (Oitrus Li- Common Fig (Ficus ca- 



monuni ) rica) 



Swett Orange (Cauran- Adam's Needle (Yucca 



tium) gloriosa) 



Olive (Ulea europsea) Almond (Amygdalus 



Australian Blue Gum commitnis) 



tree (Eucalyptus globu- Horse Chestnut (^Escu- 



lus) lus hippocastanum) 



"By means of simultaneous observation on these 

 plants, or a small number of them, it will be easy to 

 lay down on a map isophenal Hues similar to, but 

 by no means identical with, the isothermal lines 

 laid down by meteorologists ; and thus produce a 

 diagrammatic representation of corresponding climates, 

 and the difference of one station from another." 



Following up this subject Mr. Roberts discusses, in 

 the Transactions of the Sanitan/ Institute of Great 

 Britain, the evidence afforded by plants as to the 

 relative degree of purity of the air in large towns, 

 and he gives a diagram representing a series of squares 

 one within the other. Thus, in his illustration it is 

 shown that in the outermost square the Larch, the 

 Scotch, Fir, and the Heather, will grow and lichens 

 may be found on the trees In the succeeding square, 

 supposed to represent a rnore deteriorated atmospheric 

 state, the plants included in the outer square will 

 not grow, but the Sycamore, the Horse Chestnut, the 

 Yew, the Deodar, the Arbutus, the Laurustinus, and 

 various fruit trees will still thrive, which they 

 will not do in the next square, and so on, till we 

 come to the central space, in which — doleful spot — no 

 plants at all are mentioned ; but even here Poa annua, 

 and Polygonum aviculare, and Docks will grow, as 

 every one who will visit the courts and alleys of 

 Loudon can see for himself. 



Some quarter of a century ago and more there was 

 a tradition that evergreens would not grow in London, 

 and, therefore, the squares were planted with Privets, 

 and Lilacs, the deplorable aspect of which in the 

 winter months was but too familiar. People are begin- 

 ning to fiud out, however, that many evergreens do 

 relatively well in the most confined places, especially 

 those with thick leathery leaves like the Holly or 

 Yuci-a, and which are well provided with chlorophyll 

 and consecjuently proportionately vigorous. Conifers, 

 as a rule, do not do well iti such place-, indeed one of 

 the best rough tests of the purity of the air may be 

 obtained by the observation of the common Arbor- 

 vita;, Thuia or Biota orientalis. If the reader will wend 

 his way froiii the suburbs, say at a distance of 4 or 

 5 miles frow the Tha.mes on cither side towards th„ 



banks of the river, he will have ample opportunity 

 of noting how the lower branches of this shrub 

 gradually become denuded of leaves, till at length the 

 wretched plant resembles a disorganised Birch-broom 

 with a few lo;ives at the top, and then it disappears 

 entirely. Much to our surprise, however, we kuovv of 

 cases in which Pinus excelsa grows in localities where 

 the Biota will no longer do so. 



As a matter of practice much depends upon the 

 care bestowed by those in charge. Frequent cleansing 

 with a syringe or garden-engine will enable plants to 

 grow in the most unlikely places, and in the cases 

 we have in view this demands so little time and at- 

 tention that we can but press it on the attention of 

 the Society over which Lord Brabazon presides. We 

 know from our own experience of a garden where 

 Eoses had long since ceased to blow, but where now 

 not only a large assortment of choice evergreens may 

 be found, but where also an occasional Moss Rose may 

 now be plucked ; and this we attribute, not to any 

 improvement in the atmosphere, which is probably 

 more smoky if not fouler ihan formerly, but to in- 

 creased attention to syringing. 



It is obvious that the sources of fallacy and ex- 

 ception are so numerous that it will be long before 

 we can speak with any degree of statistical precision. 

 Such an amount of precision is, however, quite within 

 the bounds of probability, and it must be attiined 

 by extended comparative observations on plants under 

 all conditions and circumstances, such as IMr. Roberts 

 advocates from the point of view of hygiene, — Gardenern' 

 Chronicle. 



THE 



PKOCESS OF LIMING. 

 No. II. 



Last week we drew attention to the many good 

 effects which may result from the proper application 

 of lime to the soil, and recommended the more ex- 

 tended use of this material in Victorian agriculture. 

 It is well to bear in mind, however, that these good 

 effects are to be expected only from the proper use 

 of lime. When used improperly there may, on the 

 one hand, be no results whatever, either good or bad, 

 in which case the time and labor and money spent 

 will have been thrown away; or, on the other hand, 

 the soil may receive absolute injury, the rectification 

 of which will involve a further expenditure of labor. 



There is one case in which lime may always be 

 used without fear of injury, iu which, indeed, it must 

 be used if the soil is to be brought into a thoroughly 

 healthy condition. We refer to the case of the land 

 being sour. There is no doubt that very many, pro- 

 bably the majority, of Victorian soils are sour. Most 

 newly cleared lands are sour, and it is a frequent 

 custom to let such lands remain ioif a year or more 

 uncultivated, in order to sweeten. The sweetening 

 could be effected at once by a dressing of lime. 

 When these newly cleared lands are exceptionally rich, 

 their fertility may be, and indeed often is, such as 

 to mask the effects of their sourness, and abundant 

 crops can be obtained, even though the soil has nob 

 been sweetened. But where the soil is of poor or 

 only medium quality, it is useless to expect large 

 returns without the use of lime. 



We may here remark that it is often regarded as 

 unnecessary to add lime to soils in limestone country. 

 Yet several iustances are known of soils actually rest- 

 ing on a limestone bed which yet are almost ilestitute 

 of lime ; and in many other cases the amount of 

 lime is so small that it is not sufficient to neutralise 

 the natural sourness of the soil. The reason for this 

 apparently contradictory condition of things is not far 

 to seek. The lime is washed away from the surface 

 by the rain, and either runs off with the drainage 

 waters, or forms a layer at the bottom of the soil- 

 Sometimes this layer forms a hardened cake, and is 

 then one of the many forms of "hard pan," being 

 then known as a lime pan. Iu these esses of lime- 

 less soils in limestone; country subsoil ploughing should 

 be resorted to ; or if the limestone is too deep, then 

 trtmches may be dug along the fields and the lime- 

 stone or marl thrown up from these and spread over 

 the surface. 



