JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
888 
[ October 26, 1882. 
from the West and elsewhere as to the best method of preventing 
streams from encroaching upon their banks. Lining the banks with 
a row of Willows is a very ancient practice, and probably there is no 
better 'method. Their roots, especially in wet ground, form dense 
masses of fine fibres, well suited to retain the soil in place. The ease 
with which such a barrier is established is greatly in its favour. 
Cuttings of almost any size readily take root. These may be a foot 
or two long and as thick as one’s finger, or they may be large enough 
for fence posts, according to the readiness with which they can be 
procured. While the roots are useful for preserving the bank, the 
tops may be turned to good account to afford fuel or poles for various 
purposes upon the farm. Another use for Willows is as a wind¬ 
break, to shelter the house and farm buildings, as well as to protect 
orchards and young forest trees from the prevailing winds. When 
planted for this purpose, as well as along the streams, the tops are 
made most useful by occasional pollarding. In growing Willows for 
basket-making the stem reaches barely above the ground, and the 
shoots are cut every year .—(American Agriculturist.) 
TWO GOOD ORCHIDS. 
Zygopetalum Machayi .—To gardeners who require a useful 
plant this Orchid can be freely recommended as one of the best. 
Ladies are fond of its perfume, and the plant has the very great 
merit of being easy to grow. Ours are grown amongst Cattleya«, 
but it succeeds if managed like an ordinary cool stove plant. It 
is not particular as to compost, as we have it growing in peat, 
loam, and a mixture of both. Breaks on plants in all three kinds 
of compost or soils are producing a couple of spikes each. It is a 
free-rooting plant and requires plenty of root-space. A strong 
plant with one or two breaks should have a 9 or 10-inch pot. 
When the pots are too small for the plants one spike from each 
break is the rule, and very seldom more than one break is pro¬ 
duced from a lead, while under liberal treatment more spikes 
and breaks are common. 
Cymbidium Mastersii.— I had some dried-up pieces of this 
species in 1879, just as they had arrived from India, without roots 
and with scarcely any foliage. They were at once placed in 
small pots in a compost of half sand, half soil, being arranged in 
an ordinary stove. As the pots became filled with roots they 
were repotted into others 4 inches in diameter in a turfy sandy 
compost. Some were kept in a stove temperature, others in a 
cooler compartment in which Odontoglossums of the O. grande 
type, Cattleyas, Ac., are grown. The cooler system has produced 
the finest plants. The strongest are now in 9-inch pots, and are 
producing two and three spikes of their very pretty white flowers. 
In the larger pots the compost is one consisting chiefly of turf 
with peat. The roots are very fleshy, and I think that abundant 
root room is better than keeping the plant too much confined.—B. 
THE MANURIAL VALUE OF PHOSPHATE OF 
MAGNESIA. 
It would appear, then, that there is every reason to suppose, 
judging by their respective solubilities in water (I take Voelcker’s 
determinations, as they appear to be more complete and system¬ 
atic than any others I am acquainted with), that the following 
would be the order of the manurial activity of the undermentioned 
phospbatic substances. Peruvian guano and bone dust have, 
associated with them, organic matter or salts of ammonia, which, 
as has been shown, materially increases the solubility of phosphate 
of lime. 
1, Phosphate of lime, as it exists in superphosphates.perfectly soluble. 
2, Precipitated phosphate of lime .... soluble to the extent of 5-56 gr. per gal. 
3, Phosphate of lime in Peruvian guano „ „ „ 2‘52 „ 
4, Bone dust, mean of the two extremes „ „ „ P69 „ 
6, Coprolites. „ „ „ 0‘64 „ 
6, Estremadura phosphorite. „ „ „ 0T0 „ 
The admixture of organic matter or salts of ammonia, whilst 
increasing the solubility of Nos. 2, 5, and 6, would probably have 
a decreasing effect from No. 2 (in which case it is fourfold) 
downwards. 
In the cases of some of the field trials hereafter alluded to the 
term “ retrograde ” or “reduced phosphate” is used. It is perhaps 
therefore necessary to explain that this condition is brought about 
by the manure in which it occurs losing some of the soluble phos¬ 
phate which it contained when first manufactured, and which 
afterwards appears, owing to the tendency of the soluble phos¬ 
phate to revert to its original condition, as precipitated phosphate, 
with which it is assumed to have an equal value. The solubility 
of such reduced phosphate may therefore be taken to be 
5 56 grains per gallon (page 361), and with water containing a 
per-cent, of sal ammoniac, 21-7 grains per gallon. This condition 
of phosphoric acid was alluded to in the remarks quoted from 
Sibson (page 317) when speaking of the unsatisfactory system of 
valuation followed by many of his brother chemists. I should 
here, too, allude to another form of phosphoric acid which is 
sometimes met with—viz., the bibasic phosphate, also an unstable 
compound, with a strong inclination, if I may so express it, to 
become ordinary precipitated or tribasic phosphate of lime. Its 
solubility is, according to Malaguti, - 100 ^ 0( j 6 , or 007 grain in a 
gallon ; but although so insoluble in water it is soluble to a large 
extent in aqueous solutions of various salts, of many organic 
matters, and especially of sal ammoniac. This is of interest, as 
Otto remarks, since it is probable that this salt is left in the soil 
by the decay of vegetables. It is also dissolved by chloride of 
calcium. 
Though less soluble in water than the tribasic phosphate of 
lime, Liebig found it much more soluble than this salt in weak 
solutions of sulphate of ammonia, common salt, and nitrate of 
soda ; but, perhaps from its tendency to revert to the tribasic 
phosphate the difference between them need not longer here 
detain us. 
1 have now to show that practical field trials bear out the 
deductions which in this and foregoing letters have been drawn 
from laboratory experiments and theoretical considerations ; and 
here we have such abundance of materials that it will be best, in 
order to avoid tediousness, to make a selection of some definite 
portion of them. The course which appears to be freest from 
objection will be to take the results of field practice recorded in 
the abstracts of papers from all countries given in the Journal of 
the Chemical Society during the last twelve months ; but so far 
as the arguments which have been advanced are concerned, I 
might equally well have taken any one of the few preceding 
years during which such experiments have been extensively 
made. 
1. No. ccxxviii., page 1072. At the experimental station of 
Kiel trials were made with Oats manured with precipitated 
calcium phosphate, Estremadura superphosphate, steamed bones, 
and dissolved bones. The superphosphate gave a heavier crop 
both of corn and straw than the precipitated phosphate, and dis¬ 
solved bones than the steamed bones. At Renow-Dombrowo in 
Posen experiments were made with different manures on Potatoes. 
The soil was about 12 cm. deep, resting on a sandy subsoil, with 
large stones and marly loam underneath. Part of the manure 
was ploughed in with a subsoil plough, and the rest applied as 
top-dressing. 
2. The relative yield was as follows : the plots contained each 
one morgen :— 
Potatoes. 
1.—2 centmers Chili saltpetre. 
45 centmers. 
2.—1 
„ and 2 centmers nitro- i 
j 46 
phosphate. 1 
3.-1 
„ and 2 centmers bone-) 
48 
black superphosphate j 
4.-1 
„ and 2 centmers retro- 
| 50 
graded phosphate..; 
5.—TJnmanured deeply cultivated. 
32 
t* 
6.- 
cultivated in ordinary way. 
24 
99 
The result of the retrograded phosphate is, it is observed, remark¬ 
able. 
3. By M. Maercker, p. 1073. Experiments were tried on Barley, 
Oats, Peas, Beans, Potatoes, and Beetroot. On the real Barley 
soils precipitated phosphate appeared to be of equal value with 
superphosphate, whilst on thin sandy soils the latter appeared to 
possess a slight advantage. In the case of Oats the results were 
reversed, as the precipitated phosphate was somewhat superior to 
superphosphate on sandy soils, and almost equal in value on loam. 
The experiments on Peas and Beans were so affected by bad 
weather as to be of no value. The Potatoes were also grown 
under very unfavourable conditions, but eleven experiments were 
completed ; in these the superiority of precipitated phosphate in 
the lighter soils and of superphosphate in the heavier was esta¬ 
blished. In the case of Beetroot no special results were obtained, i f 
each form of phosphate having similar effects. On the whole, 
therefore, precipitated calcium phosphate appeared to give as good 
results as soluble phosphate, especially in lighter soils ; this may 
be partially owing to the fine state of division of the former, by 
means of which it could be intimately mixed with the soil. 
4. No. ccxxix., p. 1167. By Krocker and H. Grahl. The phos¬ 
phates used were in the form of retrograde, precipitated, and 
soluble phosphoric acid and bone meal. They were employed in 
the proportion of 50 kilos phosphoric acid per hectare. The land 
consisted of a heavy clay soil well drained, and was sown with 
Oat=, Beetroot, and Potatoes ; the phosphates were applied both 
by themselves and mixed with ammonium sulphate to the extent 
of 200 kilos per hectare. Where ammonium sulphate was mixed 
with the manure a considerable increase was observed, especially 
in the case of the precipitated phosphate and bone meal. Similar 
differences were observed in the Beet, but not to so large an 
