January 14, i90b. 
THE GARDENING WORLD . 
tiliser or its equivalent will exclude importation ; that is, give 
a sufficient supply for home use, rendering the importation of 
nitrate unnecessary. We may state that this sulphate of am¬ 
monia is well known in this country as a concentrated and 
valuable fertiliser if properly utilised, it contains about 20 
per cent, of nitrogen if the sample is a good one, whereas 
nitrate of soda only contains about 15 or 1(5 per cent, of 
nitrogen. 
While acting as chemical manager to several large com¬ 
panies for the utilisation of the garbage of towns, he also made 
some experiments in the production of ammonia by destructive 
distillation. In some of the trials on a fairly extensive scale 
lie found that the yield of ammonia sulphate was 61.3 lb. from 
2,000 lb. of the moist garbage. The garbage was subjected 
to destructive distillation, and although the results did not 
show that sufficient ammonia could he obtained in this way to 
make it an economical commercial article, he thought that the 
process might be improved. If the coke ovens were in proper 
order he thought that a certain amount of gas would produce 
the steam necessary to drive the ammonia-producing 
machinery. The article obtained he regarded as a valuable 
fertilising material which could be improved by the addition 
of certain other matters. 
Another method for obtaining artificial nitrate lie described 
was the passing of a current of air over red-hot copper, whereby 
oxygen combined with the metal, thus allowing the nitrogen to 
go free. The latter was then combined with calcium darbide 
and had all the properties of a nitrate fertiliser. This product 
was somewhat expensive, but might- still be turned to useful 
account. Dr. Erlwein employed another process by which he 
combined the nitrogen of the atmosphere by using a mixture 
of powdered charcoal and lime in an electric furnace. Ex¬ 
periments showed that the article produced by this means acted 
upon plants quite as effectively as a similar quantity of nitrate 
of potash or nitrate of soda, the latter at present being known 
as Chili saltpetre. 
Crimean Lime. 
[See Supplement). 
The above name is sometimes given to a very handsome 
species of Lime, correctly named Tilia petiolaris, but which 
has received at least nine other names, six of -which have 
originated in gardens or nurseries. It seems that there was 
some doubt about the native home of this Lime and Crimea 
was suggested. This doubt may have been particularly due 
to the fact that several of the names given it indicate that it- 
was a variety of the White or Silver Lime (T. argentea). The 
two are perfectly distinct, however, although the under surface 
of the leaves in both cases is white. It is now, however, estab¬ 
lished as being a native of East Europe, while the “ Index 
Kewensis ” says Hungary. 
The essential features of the leaf of T. petiolaris is the long 
petiole or leaf-stalk which separates it from the White Lime, 
whose leaves are short-stalked and are stiffly disposed on the 
branches by comparison with tlie Crimean Lime. 
Our supplement this week refers to a magnificent tree about 
50 ft. high in the grounds of Lord A1 den ham, Aldenham House, 
Elstree, Herts. This tree consists of a single stem, from which 
the branches on all sides droop almost from the top of the tree 
to the grass. The lower branches, as may be seen, are lying 
upon the ground. This drooping habit gives the tree the 
appearance of a weeper, and it is used for this purpose by 
many planters. The common Lime when it attains its full 
stature is more or less of a drooping habit, but the branches of 
this one are pendulous from the early stages of growth 
onwards. 
As far as we know this is the finest tree, that is, the tallest 
and best furnished, of its kind. The species is more common 
in this country than is generally supposed. Very few people 
identify it with its proper name. We have seen well furnished 
specimens even in the centre of the Highlands -where the tem¬ 
perature is frequently below zero in the winter, so that the 
tree is perfectly hardy, and, provided it is sheltered from 
violent gales, it will maintain its symmetry from the sapling 
onwards till the tree attains full size and the limit of its mum •! 
vigour. 
There are many species of Lime in the country, although, a 
a rule, they are mixed up and difficult to identify by those who 
have not studied them, but T. petiolaris is distinct in appear¬ 
ance at all stages of growth. The leaves are of large size, rich 
dark green above, silvery or hoary beneath, and have long 
petioles, especially those towards the end of the branches. This 
slender stalk enables the leaves to hang gracefully almost as 
easily as those of the Black Poplar. We presume that this is 
of advantage to leaves of such a size, as this species, at all 
events, will sometimes escape harm when the large and stiff 
leaves of T. argentea, but especially those of T. americana, get 
injured by wind and hailstorms. 
The flowers of T. petiolaris are very similar to those of the 
common Lime, being greenish-yellow, but they have the addi¬ 
tion of five petaloid or coloured nectaries. They are power¬ 
fully fragrant, and, like those of other Limes, attract honey¬ 
bees in large numbers. We presume, however, that the nectar 
or honey obtained from this tree is either poisonous or intoxi¬ 
cating, as anyone may prove for himself after a tree of this 
species has been in bloom for some days. A large number of 
bees will be found lying on the ground beneath, either dead or 
drowsy and unable to flv. The flowering period is in July, 
considerably later than our three native species. 
The tree, as represented in our picture, was just passing into 
fruit at the time it was photographed on August 19th last. 
Those who like either the flowers or their fragrance might 
therefore plant this tree to form a succession to the British 
Limes. Independently of the flowers, however, the tree is a 
valuable adjunct for parks or gardens on account of the rich 
green of tire foliage and the weeping habit of the branches. 
Our readers can judge for themselves by comparing this tree, 
which is 50 ft. high, with others of similar height, and it will 
appear narrow compared with those of more horizontal or 
spreading habit. 
One or Two Delightful Ferns for a Warm 
House. 
To attempt to write an article on suitable Ferns for a warm 
house would mean to outstrip all limits to which an article for 
these pages may run, for, as all know who are at all acquainted 
with Ferns, the numbers and charms of such as are desirable 
for the purpose in question are great indeed. There are, how¬ 
ever, some few treasures among them all that seem to steal 
further than the rest into our affections and become our espe¬ 
cial pets. Naturally we desire that our best beloved shall be 
admired by all, hence our reason for drawing attention to them 
in the hope that some who hitherto knew them not will make 
their acquaintance and add them to the treasures of their 
ferneries. 
First favourite with me among the warm-house Ferns is 
Adiantum ciliatum, truly a gem for growing on a block or in 
a shallow basket. Its long pendant fronds radiate from the 
crown and attain considerable length, the pinnae being 
arranged alternately along the whole length, the only devia¬ 
tion from this slender ribbon-like arrangement being caused 
by the young plantlets that spring from terminal buds some¬ 
what after the fashion of Saxifraga sarmentosa. It is by no 
means a- difficult Fem to grow, provided it is securely fixed on 
its block or in its basket (which must be well drained) and 
water applied with discretion. 
Widely separated but equally lovely is Mierolepia hirta cris- 
tata, a Fern that grows to considerable dimensions and makes 
a grand specimen. The fronds are long and of substantial yet 
elegant appearance, beautifully crested and of a charming 
shade of green. This is a useful Fern for exhibition or for 
decorative purposes, being capable of resisting considerable 
hardships arising from dry or impure atmosphere. 
One more I will mention and that must suffice for the pre¬ 
sent : Goniophlebium subauricula-tum is, in spite of its rather 
