74 lletrospective Criticism. 



Martial, which he and I conceived to prove that the Romans possessed hot- 

 houses. Martial says, that winter was commanded to bear the fruits of autumn. 



" Autumnum sterilis ferre jubetur Hyems," 



are, I think, his words, but I quote from memory only ; and fruits could not 

 possibly be ripened in Rome during winter without fire heat; and, as the 

 Romans heated their houses with flues, the advantage of applying those flues 

 to their fruit houses could never have escaped them. 



The most important information which you will, I think, be able to give to 

 the modern gardener respects the chemical changes which take place in the 

 sap of trees, and the motions of the sap at different periods of the year. That 

 it descends in our trees through the bark (I exclude the palm tribe generally), 

 from the leaves, cannot be questioned ; nor that it ascends through the albur- 

 num into the leaf: but that a portion of the fluid, which has become true sap 

 in the leaves, passes from the bark into the alburnum, and there joins the 

 ascending current, and feeds the young shoots and leaves, is not generally 

 understood by gardeners ; nor that the fruit is fed by similar means ; nor that 

 the sap is deposited in the alburnum, to afford materials for leaves, or to feed 

 the blossoms and young fruit of the succeeding spring. The coagulum which 

 gives the matter of the new layer of bark in the spring is derived from the 

 same source, though the arrangement of the vessels and fibrous texture of the 

 bark is given by the fluid which descends by the bark. I remain, dear Sir, &c. 

 — T. A. Knight. Downton, Dec. 17. 1833. 



Analysis of Soils. — In one of Mr. Johnson's communications on horticul- 

 tural chemistry (V. 404.), directions are laid down for the analysis of soils, 

 with so much clearness and simplicity, that I am hopeful that the day is not 

 far distant when every gardener, who deserves the name, will be able to 

 analyse soils for himself, and scrutinise every improvement in then* manage- 

 ment with the discriminating eye of a philosopher. There is, however, a slip 

 of the pen, or of the types, in the description of the process ; which, though 

 it cannot cause inconvenience to those skilled in chemistry, may prove to the 

 tyro a considerable impediment. In soils where iron is present, it may, as the 

 author of the paper directs, be separated from the other ingredients by dis- 

 solution in muriatic acid. Into this solution we are directed to drop gradually 

 " a solution of prussiate of iron." Instead of the latter substance, prussiate 

 of potass is, I apprehend, meant. The prussiate or hydrocyanate of iron is 

 the precipitated, not the precipitating, salt. Having followed with complete 

 success the plain rules laid down in this paper for the analysis of soils, I 

 recommend them to those of my professional brethren who may be disposed 

 to enter on such investigations. — Ephehicus Horticultor. Nov. 1. 1833. 



Fountains for the London Squares. (IX. 539.) — No one launches out ever 

 so little in print, but he finds the small fry of the Aristarchus tribe ready at 

 their post to give their veto, or their fiat, to whatever even the humblest may 

 assay. My London-square fountains have come in for their share ; and, among 

 the sapient remarks directed against their adoption, none, I think you will say, 

 are more amusing than the objection made against them from the ducking His 

 Majesty's liege subjects must inevitably get, if they walk on the weather side 

 of one of my 60 ft. jets in a windy day. If a man were to build a villa proxi- 

 mate to the Falls of Niagara, one might truly say, that, under the favour of 

 a brisk wind, he might find himself rather oftener than he liked in a Scotch 

 mist ; but to suppose that any thing short of a hurricane would throw a jet of 

 water 60 ft. in height, and of proportionate diameter, more than its own 

 elevation in a lateral direction, looks very like the suggestion of one of the 

 wise men of Gotham ; and, if blowing a hurricane, why need the jet play at all ? 

 The same art that bids it rise triumphant into air can bid it sleep; and 

 therefore, as far as that goes, I must think, " cadunt quaestio et argumentum'* 

 [the question and argument both fall]. — William Mason,jun. Necton, Nor- 

 folk, Nov. 1833. 



Mr Ballard's Treatise on the Nature of Trees, and the Pruning of Timber 



