132 
ON THE CULTIVATION OP THE CHERIMOYER, AND 
cool, and be covered with Dew ; the central part of the varnished circle — that under 
the small disk — will remain perfectly dry, whereas the outer metallic band is wetted 
to its very edge if the atmosphere be extremely damp. 
" Another less expected and more interesting phenomenon also occurs ; it is the 
exact repetition of the same appearances on the under surface of the large disk — 
that turned next the ground ; for Dew begins to appear on this surface, exactly 
opposite the exterior varnished band ; a light whitish circle suddenly is seen on the 
polished metal, and after becoming better defined, spreads little by little, sometimes 
as far as the edges of the plate in one direction, but never reaches the centre, which 
remains quite dry and brilliant, like the corresponding portion on the other side of 
the disk, and the small circular roof which covers without touching it." 
From experiments with this simple apparatus, M. Melloni concludes that " Dew 
does not fall from the sky, because the upper disk is always dry, and the greater 
part of the lower one is wetted. It does not arise from the ground, because if the 
exterior part of the lower surface of the great disk is covered, the middle part of it 
remains perfectly dry and brilliant. The appearance of the Dew, first on the 
uncovered band of varnish, and its extension to the adjacent and opposite (or under) 
parts of the great disk, together with the fall of temperature observed on the 
varnished cases of thermometers exposed freely to the air, demonstrate that Dew is 
a pure consequence of nocturnal radiation, which gives to good radiators the degree 
of cold necessary for the condensation of the elastic invisible aqueous vapour which 
pervades our atmosphere." 
The article for August shall place the reader in possession of some facts, and 
their bearings, which may perhaps afford ground for reflection, and a comparison of 
phenomena somewhat at variance with those which the advocates of radiation have 
claimed as the foundation of their hypothesis. In the meantime, we are in posses- 
sion of two more letters by M. Melloni, in the last of which he makes it appear that 
some of the editors of our periodicals have either mistaken or misrepresented his 
objects, and that he did not intend altogether to sanction Dr. Wells's theory, or 
justify the conclusions at which he arrived. We ourselves observe nothing very 
satisfactory in M. Melloni's papers, but further observations must be postponed to a 
future occasion. 
ON THE CULTIVATION OF THE CHERIMOYER AND OTHER 
SPECIES OF CUSTARD APPLES, AS FRUIT TREES. 
The Cherimoyer, or soft-fruited Custard Apple, is the Anona Cherimolia of our 
botanical catalogues, but was called Anona tripetala by Sims, in the " Botanical 
Magazine," t. 2011, and by Aiton, in his " Hortus Kewensis," ii, p. 252. This 
genus, in connexion with several others, forms a natural order called Anonacece. 
A. Cherimolia forms a tree-like shrub, twenty or thirty feet high. The leaves 
