April 2, 1900,] Supplement to the " Trojncal Agriculturist " 
719 
a pest which had previously baffled the skill 
of experimeuters. The Dulmeiij' experimeuters 
knew that a heavy dressing of caustic lime 
would kill the germ of firiger-and-toe, but it 
would also kill the nitrifying and other advan- 
tageous soil organisms, while, on the other 
baud, a small dressing of 4 cwts. per acre 
would be insufficient to kill the disease germ. 
They therefore steered a middle course so as to 
avoid the Scylla on the one hand and the Charyb- 
dis on liiB other, by applying one ton of ground 
lime per acre when the land was being ploughed 
in the autumn, and another ton per acre when the 
laud was being worked in the spring, In this 
cas« they rigidly avoided the use of dissolved 
phosphates and used undissolved phosphates sup- 
plemented with 8 cwts. kainit and 1 cwt. sulphate 
of ammonia- This treatment proved a complete 
success, and the root crops grown by this system 
on infested soil were found to be sound and 
good, while those grown on the same soil under 
different treatment were so rotten as hardly to 
be worth removing. It was noted, however, that 
though this treatment was successful in eradi- 
cating the disease, the crop was decidedly smaller 
than that grown on uninfested land to which 
only a tenth of the same amount of lime had 
been applied. A word in conclusion may be 
added as to the far-reaching efifct of the Dulmeny 
experiments. When these experiments were com- 
menced, ground lime for agricultural purposes 
had never been heard of, whereas now there are 
fit least six lime works where extensive grind- 
ing 'plant' is kept hard at work to supply 
the ever-iucreasing demand for that substance. 
Since the principles of the New Soil Science 
have been put in successful practice at Dulmeny, 
the scientific authorities, who at first had branded 
these principles as absurd heresies, have changed 
their tune, and in the recently-published volume 
of the Highland Society's Transactions, the chemi- 
cal adviser of that society has unreservedly 
declared his acceptance of these new doctrines* 
Great credit is due to Lord Rosebery for nnt 
only providing the means of carrying on this 
important research work, but also for throwing 
his home farm and experimental grounds open 
for the inspection and information of agricul- 
turists. 
[Note hy the Editor A(/ncultural Magrxine, 
—•'Years before /Hellriegel announced his 
discovery in 1886, Messrs. Hunter and 
McAlpine were teaching the same fact to 
their students, as the lecture notes of any of 
their studetits at that time can testify." As a 
Student both of Mr. John Hunter, one of the 
extra-mural teachers of Agricultural Chemistry, 
and Professor McAlpine, the popular lecturer on 
Botany at Minto House, we can fully endorse 
the above from our personal experience a« well 
as from our ' lecture notes,' and it gives us 
very great pleasure to press the claims of our 
old teachers in Edinburgh to the discovery, as 
indeed we did in the pages of the Agricultural 
Magazine as soon as we read of " Hellriegel's 
discovery" shortly after nnr arrival in the Ishind. 
To us the " new theory ' was familiar enougli 
from acquaintance gained in the class-rooms at 
Edinburgh."] 
THE SOLUBLE MINERAL MATTER OF SOIL.«. 
By Thomas U. Means. 
Assistayit in the Division of Soils V.S. Dept. of 
Agriculture. 
{Concluded.) 
If in the piece of granite referred to in the 
beginning of this paper the rain water had not 
been allowed to wash out the soluble matter ns it 
was formed, there would have been found a 
quantity of white salt in the rock powder and in 
the resultant soil. If the quantity of this white 
salt had been great, as much as 2 or .3 per cent of 
the weight of the rock, it would have been 
difficult or impossible to get a plant to grow in the 
soil. This has been the experience the world 
over, that plants will not gro^v in a soil that con- 
tains too much soluble matter. 
In arid countries there is not sufficient rainfall 
to remove all of the soluble matter as it is formed 
i:i the d ecay of rocks and soils, and the result is an 
accumulation of .salts within .the soil. In still 
other parts of the country, where more rain falls, 
the sales may be washed out, but the solution runs 
down into inclosed basins having no connection 
with the ocean, and there evaporates, depositing 
the salts. In either of these cases plants suffer 
when the amount of salts reaches a certain per 
cent. It can salely be said that few ci'cips can 
flourish when soluble matter amountincr to one- 
half of 1 per cent of the weight of the soil is in 
solution around the soil grains when tha soil is 
saturated with moisture. As the water of satu- 
ration weighs from 25 to 75 per cent of the dry 
weight of the soil, it will be seen that crops will 
not thrive when the solut;ion contains more than 1 
per cent of the soluble matter. When the con- 
centration of the soil solution reaches this per cent, 
the leaves of alfalfa turn yellow, wither, and die, 
just as the plant would do if drought prevailed. 
In arid regions where the amount of rainfall it 
small, the amount of water which leaches through 
the soil is not sufficient to wash out all of the 
soluble matter. For this reason the amount of 
soluble matter in the western soils exceeds the 
amount of soluble matter in the eastern soils of 
the United States. The following table shows th« 
relation between the amounts of soluble matter in 
the soils of different parts of the country : — 
Relative amounts of salts in soils. 
Kind of soil. 
toc.iiity. 
Prairie 
Limestone 
595 
245 
Kansas, Nebraska ... 0 038 1,155 
Virginia, Maryland. Penn- 
sylvania, Kentucky ... -017 
Gneiss ... Virginia, North Carolina -077 
Truck ... Maryland, Virginia, 
North Carolina ... -qog 01 0 
Subtropical. Florida ... .qqj2 
The prairie soils throughout the West show large 
amounts of soluble matter, and they are exceedinelv 
productive when enough rain falls to keep the ^oil 
i 1 a moist condition. Of the soils of the humid 
regions, those formed from limestone show the 
greatest percentage of soluble matter. In general 
