JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
[ June 8, 1882. 
471 
mode of causing a rapid germination in Turnips, Spinach, and 
other seeds in dry weather. Small seeds sown in beds are 
watered the same way, and mats placed over them until the 
seedlings make an appearance. The question of watering plants 
grown in pots and other matters we leave till another opportunity. 
—A Nor’-easter. 
NEW THROTTLE VALVE. 
At the late Show of the Royal Horticultural Society a first-class 
certificate was awarded to Messrs. Foster & Pearson for the 
valve represented in the annexed engraving. This is a distinct 
improvement on the patent valve introduced by the same firm 
two or three years ago, inasmuch as the working parts of the 
present valve can be taken out should the wing or disc be set fast 
in any position. Other valves that we have seen cau only be 
removed in a particular position, either when open or closed. The 
valve is also as durable as convenient, the working parts being of 
brass, and at any time can be separated from the cover, taken out 
and cleaned. A in fig. 94 represents the cast iron of the valve, 
Fig. 94. 
which closes the aperture when the working parts are removed ; 
B the brass seat of the valve in which the wing works, and c the 
screws by which the cover is secured ; thus the valve is as simple 
as it is effectual, and thus recommended itself to the Judges of the 
Show, who at once perceived its advantages. 
THE PRODUCTION AND LOSS OF NITRATES 
IN THE SOIL. 
An esteemed correspondent has sent us the following lecture 
from the Gloucestershire Standard, which we have not been able 
to insert sooner. It was delivered some time ago at the Royal 
Agricultural College, Cirencester, by Mr. Robert Warrington, 
formerly a pupil of Dr. Voelcker and Professor Church, and now 
engaged with Sir J. B. Lawes and Dr. Gilbert in the prosecution 
of important work at Rothampsted. Mr. Warrington, it may be 
added, is the author of some valuable articles contributed to 
the “ Dictionary of Chemistry,” of the useful handbook “ The 
Chemistry of the Farm,” and is a member of the Council of the 
Chemical Society. We readily print this able lecture, pertaining 
as it does to a subject of importance to gardeners as well as to 
farmers :— 
The lecturer first explained that nitrates were produced as part of 
the living functions of a very low order of living organisms (Bacteria) 
present in the soil. The action was analogous to that of the Yinegar 
Plane. This discovery of the exact mode in which nitrification was 
carried on in the soil was made by two French chemists, and the scien¬ 
tific world had only been fully acquainted with the process for about 
five years. The lecturer then described a few simple experiments by 
means of which the fact that nitrification is due to the action of living 
organisms in the soil could be demonstrated, and adduced an addi¬ 
tional proof in the circumstance that anything which would destroy 
the organisms would stop nitrification. The former supposition 
viz., that nitrates were produced by mere surface oxidation, was thus 
proved to be erroneous. _ . 
The conditions necessary to nitrification were, first, that the soil 
should be freely in contact with oxygen, for nitrification was a pro¬ 
cess of oxidation. Next, the soil must be moist. The more wet the 
soil was the more would nitrification be assisted, provided the water 
was not so abundant as actually to choke the pores of the soil. 
Thirdly, the soil must contain some salifiable base for the nitric acid 
to combine with when it was formed, for if the base was not present 
the process of nitrification would soon cease. In the fourth place, 
a favourable temperature was necessary. The process of nitrification 
would take place, it was true, at a very low temperature, nearly at 
freezing point (he had had it going on at 3° Cent.), but in a summer 
temperature the process was wonderfully accelerated. The^French 
chemists said that the most favourable temperature was about 37° Cent., 
when it would take place ten times more rapidly than it would at 14°. 
The process went on most rapidly in the surface soil, and that for two 
reasons—first, because there was on the surface a greater abundance 
of nitrogenous organic matter, the remains of animal and vegetable 
life ; and, secondly, the surface soil came more freely into contact with 
the oxygen of the air than was the case with the subsoil. 
The production of nitrates in the soil was a subject of very great 
agricultural importance, because scientific studies had clearly pointed 
out that of all forms of nitrogen nitrates were those most suitable 
for plant food, and in the case of cereal crops it had been established 
that nitrates were practically the only form of nitrogen which was 
adapted for the Wheat crop, and on which it fed with advantage. 
Thus the crop of Wheat or Barley to be obtained from the soil de¬ 
pended principally on the amount of nitrates which that soil contained. 
The subject became of new importance when they considered one of 
the properties of nitrates—viz., their great solubility and their great 
uiff usibility ; in fact, for them the soil had no retentive power. W ith 
some other substances this was not the case. Superphosphate, for 
instance, was readily retained ; but for nitrate of soda the soil pos¬ 
sessed no retaining power, and the permanence of it in the soil was 
at the mercy of the weather. It would, therefore, very easily slip 
through their fingers, and for that reason it was more worthy of their 
consideration. 
He next referred to the results obtained at Rothamsted by means 
of their drain gauges. Some ten years ago Mr. Lawes desired to 
know the amount of drainage that passed through the Rothamsted 
soil. The amount of rainfall had been recorded for many years, and 
they wanted to know how much of the rain passed through the soil. 
Three blocks of soil was therefore isolated—that was to say, a trench 
dug round them, and the soil built in with bricks ; the blocks were 
undermined, and cylinders were placed underneath in which the 
water draining through the soil was collected and measured. These 
drain gauges had been in operation for eleven years, and during the 
last five years the whole of the water coming through had been 
analysed, with the special object of ascertaining what was the 
quantity of nitric acid being formed in that soil in the course of the 
year. The blocks of soil were unmanured, and were kept free from 
vegetation, and were agriculturally in the condition of bare fallow. 
The table of results showed that the amount of nitric acid coming 
through was very considerable about the month of July, the average 
of five years for that month giving the amount at 2'78 lbs. per acre. 
In the month of August the amount increased to G'68 lbs. per acre. 
During all the autumn months there was a great deal more nitric acid 
coming through than in the spring months. That exactly followed 
what he told them about the facilities afforded by summer tempera¬ 
ture for the pi-ocess of nitrification, for it was after the summer, when 
the autumn drainage began to flow, that they got the greatest amount 
of nitrates coming through. The average of the two sizes of drain 
gauges, 20 and 60 inches deep, showed that during the five years they 
had in one case 44'8 lbs. of nitrogen per acre per year draining 
through the soil, and in the other case 42 - 6 lbs. of nitrogen per acre 
per year. That was a very great amount of nitrogen to pass through 
the soil in the drainage water, and until those results were obtained 
they had no notion that such an amount would come away. An 
average Wheat crop of 30 bushels per acre only contained 45 lbs. of 
nitrogen, and here they had an average of 42 lbs. and 44 lbs. being 
lost by drainage, the highest amount in one year being 63 lbs., and 
the lowest 28 lbs. 
He then proceeded to tell the amount of nitrates found in bare 
fallow. Samples of soil had been taken at Rothamsted, in two fields 
under bare fallow, of the first depth of 9 inches, the second depth of 
9 inches, and the third depth of 9 inches. In one field the whole of 
the 27 inches yielded 58'8 lbs. of nitrogen per acre, and in the other 
the amount was 56 - 5 lbs. But at the third depth of 9 inches they 
had not got to the end of the nitric acid, and no doubt if they had 
gone still deeper a further quantity would have been found. The 
greatest quantity of nitric acid was found in the second 9 inches. 
They generally found that the salts in the soil lay in bands, and it 
was very seldom that they were equally distributed throughout; the 
cause of the greatest quantity of nitric acid being found in the second 
depth was very simple. The nitrates were produced on the surface 
of the soil, and a few weeks before these samples were taken there 
had been a heavy fall of rain which had washed them down. They 
saw that the results which he had mentioned really gave them the 
reason why bare fallowing should be an operation calculated to so 
