THE FAKMER'S MAGAZINE. 



155 



Nitrogen. 



In the two plants 05394 



Inttiesoil 001705 



Total 007099 



There was in the seeds 0'05 146 



Nitrogeu gained in seventy-two days' vegetation, by 



both plants 01953 



By one single plant O'0O97C 



These results, identical with those obtained by the 

 experiments made in 1856, corroborate the fact, that in 

 the open air, in a soil where there are only phosphates 

 united to other n)ineral salts, a plant grows with a 

 certain vigour only in the first period of vegetation, as 

 long as the nitrogenous constitutional substance of the 

 seed suffices to the formation of the organs. Beyond 

 that limit, the plant becomes languid and sickly, and 

 rather a substitution than an increase of organization is 

 observed. 



This is clearly seen in the following tables, in which 

 are stated the facts 1 have just explained. 



Second Experiment. — Vegetation o^ Helianthuses 

 in the open air, in a soil of Calcined Sand, contain- 

 ing no Phosphate of Lime, and being manured with 

 Nitrate of Potash only. 



In flower pots, previously heated to a red heat, some 

 granulated calcined white quartzy sand was placed, mixed 

 with some nitrate of potash. 



In the flower-pot No. 1, weighing 3332*5"gr8., were 

 put — 



Uuartzy sand 10,230 grains. 



Nitrate of potash 4*65 put in at once. 



Into the flower-pot No. 2, weighing 9300 grains, 

 were put- 

 Quarry sand 33,25017 grains. 



Nitrate of potash ...... '5 Buccessively put in. 



In each of the pots two seeds of Helianthuses weigh- 

 ing 1*798 grains were placed : they were watered with 

 water perfectly pure. 



Seventeen days after, the two first leaves were formed, 

 and the second were already visible. 



After thirty days, the second leaves were developed. 

 All the plants appeared strong and healthy ; the cotyle- 

 dons had a dark greenish hue. Nevertheless, black 

 spots were already visible at the extreme ends of the 

 first leaves. It was from this symptom that I thought 

 it advisable to examine the plants, because it showed 

 that they were about to enter into the period of deca- 

 dence. 



The plants of pot No. 1 were dried up, and they 

 weighed 18'0885 grains. 



The analysis indicated the following results : 



la both plants 



In the soil and the pot, nitrate 17856 1 

 equivalent to J 



Total of nitrogen found 



There was in the two seeds .... 0"057660 1 

 In the 4-65 of the nitrate added 0643560 J 



Nitrogen. 

 0-367815 



0247225 



0615040 

 0.701220 



Loss of nitrogen in thirty days' vegetation 0086180 



The land did not contain any carbonate of potash. 



Within a fraction I found in the plants the nitrogen 

 which had been supplied in the nitrate and the seeds. 



It is interesting to compare Helianthuses grown under 

 the sole influence of nitrate with the same plants of the 

 same age which had been grown in 1856, in a soil mixed 

 up with nitrate and phosphate of lime. 



Stems. Leaves . 

 In 1 856, soil with nitrate and phosphate 10 to 12 in. 2^ ia 

 In 1857, soil with nitrate only 2^ in. A\ in. 



It is not doubtful that the absence of phosphate of 

 lime in the soil had checked the progress of vegetation ; 

 but it is quite evident that, alone, nitrate of potash had 

 produced a better effect upon the development of the 

 Helianthuses than phosphate of lime added to the soil 

 without the concurrence of a manure containing soluble 

 nitrogen. To prove it, it is only requisite to compare 

 the results furnished by the plants No. 2, of the first 

 experiments, which had nothing but phosphate, with 

 those which I have just mentioned. 



Dry weight. 

 Grains. 



Helianthus No. 2, thirty-three days old 5115 



Three and four-tenth times as much as the seed; 



Helianthus No. 1, second experiment, 30 days old. IS'OSS 



Ten times as much as the seed. 



No. 2 took of carbon from the atmosphere 1.705 



No. 1 took of carbon (second experiment) 6'510 



On the fiftieth day, the stems of the remaining 

 Helianthuses No. 2 (second experiment) were 3^ to 

 3| inches respectively in height. The cotyledons were 

 withered ; the first leaves almost faded. The plants had 

 a sickly look. 



On the seventy-second day, the plants were 4J 

 and 8 inches high respectively. All the leaves, with the 

 exception of the fourth, were either faded or greatly 

 spotted ; the fifth leaves were just appearing, and one 

 of the plants, the highest, bore a little flower. The 

 other plant had nothing living but the stem ; it was 

 evidently on the point of dying. It was that circum- 

 stance which decided me in bringing the experiment to 

 a close. 



After drying up the plants, both were found to 

 weigh 18*2125 grains, about 0-155 grains more than the 

 Helianthuses No. I, when they were one month old, 



The analysis showed the following results : 



