368 



JOURNAL OF HOETICULTURE AND COTTAGE GARDENER. 



r October 31, 1865. 



the Ailauthus Silkworm and its moth (Bombyx Cynthia), which he 

 had succeeded in cultivating at Colchester in the open air, showing 

 satisfactorily that this species might, with a moderate amount of 

 care, become a new article of commerce in this countiy. He had 

 obtained a gi^ant of a portion of a railway embankment for a plan- 

 tation of the Ailauthus trees, which will grow in the poorest soil. It 

 ■was of importance that the eggs should be hatched upon the leaves 

 of growing trees, as the young larvip did not thrive well on gathered 

 leaves, a circumstance completely contrary to the Imbits of the com- 

 mon Silkworm. The moths hatch from the cocoons at a temperature 

 of 70°, and he had procured two broods during the present season. 



Mr. W. W. Saunders made some observations on the comparative 

 value of the Ailanthus, contrary to the statements of M. GuiJrin 

 Mcueville in its favour. 



Mr- S. Scudder, Secretary of the Natural History Society of Boston, 

 U.S.A., also made some observations on the cultivation of silk from 

 the Bombyx Poly|)hemus, in North America, the cocoons of which 

 very nearly resemble those of the Ailauthus Moth. He also exhibited 

 a remarkable fossil insect, allied to the genua Ephemera, and which 

 must have measured as much as 5 inches across the expanded wings, 

 which had been found by Mr. Hart in the Devonian Rocks of New 

 Emnswick. 



Mr. Sydney Saunders exhibited a fine series of specimens of the 

 Bee parasite, Hylechthrus Rubi, in different stages of growth, found by 

 him at Corfu; and Mr. T. Bond several vei-y beautifully preserved 

 specimens of the catei-pillars of British Moths. 



A paper by Mr. F. Walker, containing the description of a new exotic 

 genus of Chalcididie, was read ; also, the continuation of a memoir 

 by Mr. C. "Wilson, of Adelaide (South Australia), on the Bnprestidae 

 of Australia, of which beautiful family he believed there were not 

 fewer than SUO native species, 350 of which inhabited southern 

 Australia, a fine woi'k by Si. Henri DeyroUe, upon the si>ecies of the 

 same family, collected in the Malayan Archipelago, by Mr. Wallace, 

 was also esJiibited. 



An interesting conversation took place on the various peculiarities 

 which had been observed in the development of insect life during the 

 two last unprecedeutcdly dry and hot seasons. 



IlECENTLY-DISCO\^RED PHOSPHATIC 

 DEPOSITS IN NORTH WALES. 



BY DE. VOELCKEI!. 

 {Read at the Slectinri o/ the British Association at Birmingham.) 

 The discovery of new supplies of pbosphatie materials, it is 

 scarcely necessary for me to say, is of the highest importance 

 to the English agriculturist, who, in the shape of superphos- 

 phate and similar artificial manures, consumes annually many 

 thousands of tons of phosphatic fertilisers, the demand for which 

 is yearly increasing, not only in this country, hut on the con- 

 tinent and in the colonies. Under these circumstances it is 

 fortunate that from time to time fresh mineral deposits are 

 discovered, and others are made available for manufacturing- 

 purposes, which previously were known only as objects of in- 

 terest to the geologist or mineralogist. 



Those engaged in the manufacture of artificial manures, or 

 of phosphorus, are well acquainted with the fact that bones. 

 South American boue-ash, Cambridgeshire and.Sufiolli copro- 

 lites, apatite from Canada, phosphorite from Spain, Sombrero 

 rock-guano, )ihosphatic guanos from the South Pacific Ocean, 

 and other varieties of mineral phosphates, find a ready sale, 

 and are largely consumed by manufacturers of manures in this 

 coimtry. 



Apprehension has. indeed, been expressed that with the 

 yearly increasing demand for phosphatic manures the supply 

 for the raw materials could not keep pace. Such apprehensions, 

 however, appear to me to have no foundation, for new sources 

 of mineral phosphates are rendered practically available at the 

 present time, and a very extensive mine has recently been 

 discovered in North Wales. This mine contains, besides 

 copper and iron pyrites, two phosphatic minerals, both of 

 which are of considerable importance to the English agricul- 

 turist. One of them is a phosphatic Umestone, the other a 

 black shale, largely impregnated with phosphate of lime. 



These minerals were discovered recently by Mr. Hope Jones, 

 o! Hooton, Cheshire, whilst he was searching for other minerals 

 inthe neighbourhood of a place called Cwmg^Tien, about twenty 

 miles west of Oswestry. The phosphate deposits occur not far 

 from the clay slate and lead-bearing districts of Llangynog. 

 The rocks are Silurian, of the Llandilo series, and a large 

 fault south of the vein and parallel to it brings in the Denbigh- 

 .shire grits. Cross faults north and south also occur, which 

 are highly metalhferous, containing ores of copper, lead, man- 

 ganese, &c. The strata (slaty shale) contains several beds 

 of contemporaneous felspathic ash and scoriai ; and the 



usual fossils of the LlandUo series are found, but not in great 

 numbers. 



Mr. Hope Jones has traced the phosphatic beds a long 

 distance, and informs me that they are continuous for about 

 two miles. I have myself visited the jihosphatic mine at 

 Cwmgynen, and on that occasion collected various specimens 

 of limestone and black phosphatic shales, to the composition 

 of which I shall presently refer. 



The black phosphatic slate or band is fully 18 inches thick, 

 and the limestone bed from 8 feet 6 inches to 9 feet. The 

 vein which separates the two deposits from each other is 14 to 

 16 inches wide, and filled ))artiaUy with white pipeclay, calca- 

 reous spar, and copper and iron pyrites. The deposits are 

 readily approached by a horizontal passage which has been 

 driven into the vertical beds of phosphatic minerals. Tha 

 high level is only 76 feet long, and close to the summit of the 

 hill. The average depth from the summit level to the drainage 

 level is about r)00 feet, and the distance here to the phosphatic 

 deposits about 100 yards. 



At present the mine is approached only by the summit level ; 

 but experience having shown that the black band widens as 

 the depth gets lower, operations have been begun at Cwmgynen 

 to drive a horizontal passage into the hill at a depth of about 

 206 feet below the upper level, which passage is now being 

 driven with as much rapidity as is possible, and will probably 

 be completed in about three months, when a large supply of 

 the phosphatic deposit will be obtainable. 



The bed of black shale is 18 inches in thickness. This shalo 

 contains variable quantities of phosphoric acid. Towards the 

 summit of the hill it is not nearly so rich in phosphate of Ume 

 as at a lower depth. Thus, in specimen No. 3, taken from a 

 higher level, I find only 24.07 of phosphoric acid, equivalent 

 to 48i percent, of tribasio phosphate of lime ; while in another 

 sample, taken at a lower level, I find as much as 29. (i7 of phos- 

 phoric acid, which is equivalent to 64.16 per cent, of phosphate 

 of lime. 



The mine of Cwmgynen, as worked at present, produces 

 specimens containing from 54 to 66 per cent, of phosphate of 

 Hme. Blocks weighing above 1 cwt., I am informed, are now 

 worked out, which resemble intimately the specimen in which 

 I find 64 per cent, of phosphate of lime. 



The black band contains no carbonate of lime, little mag- 

 nesia, some fluoride of calcium, alumina, and oxide of iron, 

 soluble in dilute acids, and, more or less, iron pyrites. In 

 some specimens I find much less sulphm' than in others. The 

 highest per-centage of sulphur amounts to 7.02, equivalent to 

 about I.S.J per cent, of iron pyrites. The more compact masses, 

 found at a greater depth from the surface, contain less iron 

 pyrites than the deposit nearer to the surface. The occurrence 

 of graphite in this phosphatic shale is also i^ecuhar. 



Lastly, we have to take a glance at the composition of the 

 black limestone beds. The darker-coloured varieties contain 

 more graphite, and are richer in phosphate of hme than the 

 lighter-coloured specimens. In the latter I find only from 10 

 to 20 per cent, of phosphate of lime ; in the darker varieties 

 from 30 to 35 i)er cent. The beds contain a good deal of car- 

 bonate of magnesia (5 to 8 per cent.). On burning, they fur- 

 nish a lime which is very valuable for agricultural purposes ; 

 for the farmer who applies this lime to his land not only sup- 

 plies it with lime — a constituent required by every description 

 of agricultural produce — but also with the still more important 

 mineral constituent of plants — phosphoric acid. It is scarcely 

 necessary to obsen'e that it is chiefly the phosphoric acid in 

 bones which renders the latter so valuable as a fertUiser ; nor 

 need I specially dwell on the fact that the apphcation of this 

 newly-discovered phosphate of lime is, in point of fact, almost 

 equivalent to liming and boning in one operation. 



WORK FOR THE "S\T2EK. 



KITCHEN GAItDEN. 



The recent heavy rains have somewhat impeded spade- 

 operations. The necessity of an examination of all drains and 

 water-courses will be readily suggested by the now frequent 

 recurrence of wet weather. In the course of time weeds and 

 rubbish accumulate in quantities sufficient to impair the effi- 

 ciency of the common -water-conduits, and evei'y facility should 

 be given at this season for the passage of the water ii-om the 

 garden. Beans, in soils favourable to vegetation duiing winter 

 a few Mazagans may be planted, either where they are to re- 

 main or on a sheltered border, for planting out early in the 



