264 
ACTION OF SULPHATE OF IRON ON VEGETATION. 
index, by being assisted by gravity, will move more easily. No. 2 is an Index Thermometer to show 
the greatest heat of the day; for the same reasons it is also placed on an incline, the ball end being the 
. highest. No. 4 are a pan- of thermometers called the Wet and Dry Ball Thermometers, to show the 
power of the air to evaporate water. V is a vase or cistern of water for the Wet Ball Thermometer; it 
is placed on the outside of the thermometer, to which a cotton wick is to be attached to connect it with the 
water, and at about the same elevation as the ball of the thermometer, in order that the evaporation from 
the vessel of water may not influence the thermometer on the other side, which is to be the Dry Ball 
Thermometer; for, in some careful experiments which I made with a vessel placed beneath the balls, it 
was found that the dry ball was lowered from 0-2° to 0*3°, which, though apparently a small error, is 
a serious amount in the mean difference between the readings of the Dry and Wet Ball Thermometers. 
Figure 3 is the mew of the south side of the stand. No. 3 is an Index Mercurial Thermometer, with 
a black ball to give the greatest solar heat. It is a Rain-guage on Glaisher’s construction, and B is a 
measure into which rain is to be poured for measurement. 
The Rain-guage and Wet and Dry Ball Thermometers will be described more fully in a future paper. 
ACTION OR SULPHATE OR IRON ON VEGETATION A' 
By M. NATJDIN. 
771HERE are but few persons, we should think, at the present day, who have not heard of the grand 
X discovery made by M. Eusebe Gris, of the power of sulphate of iron in rendering diseased plants 
healthy, especially such as are pale and sickly. Numerous experiments, and in particular those which 
were instituted at the museum (Paris), by M. Decaisne, have confirmed, in all respects, the facts 
announced by that acute observer. M. Gris began a new series of experiments on the use of the same 
salts as restoratives, when, unhappily, death put an end to his labours. His son, M. Arthur Gris, has, 
however, continued them; and, it' he has not, from respect to the memory of his parent, been led to exag¬ 
gerate the virtues of sulphate of iron, the results he has attained diming the year are very remarkable. 
On the fourth of May, 1849, when the weather was warm and windy, and indicated the approach 
of rain, M. A. Gris scattered over six centiares f of ground sown with grain, 500 grammes of sulphate 
of iron, bruised very fine. Two hours afterwards it was dissolved by the rain, and incorporated with 
the soil. At the gathering of the crops the grain thus treated was cut, and the returns compared with 
the produce of a similar extent of ground situated near the first and treated in the same manner, but 
not sulpliatized. The precise weights were, respectively, as follows ;—one sheaf of wheat, sulphatized, 
weighed 6 kilogrammes, 500 grammes; one sheaf of wheat, not sulphatized, weighed 4 kilogrammes, 
500 grammes ; when thrashed and cleaned with all the necessary care, they weighed respectively— 
2 kilogrammes, 420 grammes; and 1 kilogramme, 964 grammes; J thus leaving a difference of 
about one-third in favour of the crop which had been treated with the sulphate of iron, and that only 
once. We have omitted to state that all the experiments reported by M. A. Gris have been made, 
comparatively, on two patches of ground contiguously situated, in the same conditions, and subjected 
to the same culture, with the exception already mentioned. A similar experiment was made with oats, 
but it did not admit of being tested fairly, because that portion treated with the sulphate of iron grew 
so large that it was soon laid, and it was thus impossible to establish any other result than the great 
development of the stems. 
An experiment was also made with a number of melons. Eight plants were placed in an open bed, 
without any bottom heat, and under large bell-glasses ; each was watered with one litre J of sulpha¬ 
tized water. Eight other plants, of equal size, were planted near them, and received the same 
attention, except that they were only supplied with common water. By the end of June there was a 
marked difference in favour of the first plants, which set their fruit fifteen days before the others ; and 
in the course of the month of August, the first had attained twice the size. Unfortunately M. Gris had 
to absent himself about the time the fruit had attained maturity, and was therefore unable to make a 
definite report of the experiment. 
A similar result was obtained from two crops of haricots ; and the effects of sulphate of Iron have 
not been less striking with crops of potatoes, not only in the greater number of tubers, but also in their 
superior quality and colour. Experiments were also made with onions, carrots, asparagus, and cauli¬ 
flowers, and the like results obtained. Analogous effects were also produced on fruit trees, such as 
peaches, pears, and vines. 
* Abridged from the Revue Horticole. + A centiare is equal to 1-196033 square yards. 
% A kilogramme is equal to 2.20548 pounds, avoirdupois; and a gramme is a little more than fifteen grains, troy. Probably the 
French sheaf is less than ours. 
§ A litre is equal to 1.760773 pints. 
