Value of Artificial Manures. 547 
Analyses of Gemiine Samples of Peruvian Guano, &c. — continued. 
No. of 
Sample. 
Moisture. 
Organic 
Matter 
and 
Salts of 
Ammonia 
Sand. 
Phos- 
phates of 
Lime 
and 
Magnesia. 
Alkaline 
Salts. 
Nitrogen. 
Equal 
to 
Ammonia 
Phos- 
phoric 
Acid in 
Alkaline 
Salts. 
Equal to 
Soluhle 
Phos- 
phate of 
Lime. 
65 
8 
38 
55 
52 
9 
78 
11 
07 
15 
25 
17- 
08 
20- 
75 
4- 
71 
9-70 
66 
I o 
vo 
ou 
Do 
94 
22 
02 
10 
33 
13' 
22 
1 u 
06 
66 
9-60 
67 
12 
14 
52 
61 
1 
49 
24 
58 
9 
18 
13- 
47 
16 
35 
2 
71 
5-58 
68 
l(i 
92 
50 
30 
1 
78 
22 
05 
8 
95 
12- 
02 
14 
60 
3 
81 
7' 65 
69 
8 
23 
55 
62 
1 
20 
25 
30 
9 
65 
14- 
21 
17 
25 
3 
19 
6-57 
70 
11 
61 
53 
47 
1 
71 
20 
73 
12 
48 
12 
69 
15 
40 
5 
08 
10-47 
71 
12 
89 
54 
12 
1 
14 
20 
27 
11 
58 
13 
92 
16 
90 
5 
61 
11-56 
72 
7 
91 
59 
03 
1 
49 
18 
77 
12 
80 
11- 
28 
13 
69 
5 
70 
11-85 
73 
14 
85 
48 
80 
2 
66 
24 
63 
9 
06 
11 
17 
13 
56 
2 
49 
5-13 
74 
14 
48 
51 
03 
1 
46 
25 
25 
7 
78 
11 
57 
14 
05 
2 
57 
5-30 
75 
15 
06 
50 
62 
1 
87 
23 
73 
8 
72 
11 
46 
13 
91 
3 
51 
7-23 
76 
18 
67 
49 
35 
1 
21 
20 
62 
10 
15 
13- 
16 
15 
96 
2 
61 
5-38 
77 
16 
75 
51 
26 
1 
•27 
22 
52 
8 
20 
13- 
96 
16 
95 
2 
26 
4-70 
78 
11 
37 
54 
52 
0 
82 
18 
52 
14 
77 
13 
49 
16 
38 
5 
08 
10-47 
These seventy-eight analyses give us the mean composition of 
Peruvian guano, as under — 
Moisture 13-67 
Organic Matter and Salts of Ammouia * 52-05 
Sand, &c 1-83 
Phosphates of Lime and Magnesia 22-78 
Alkaline Salts, containing 3-34 Phosphoric Acid equal to) p „_ 
6-89 Soluble Phosphate of Lime / ' 
100-00 
* Containing Nitrogen 13-61, equal to Ammonia 16-52. 
Comparing these numbers with the results formerly published, 
we find that the chief difference is in the phosphate of lime. 
The percentage of ammonia indeed, as found in the samples of 
the last four years, is somewhat lower than I formerly found it, 
being, on the aveivage of the earlier experiments, 17-4, whereas it 
is in the present case 16'5 per cent. ; but it must be remembered 
that the former series was obtained direct from the cargoes, 
whilst the greater number of the analyses now recorded were 
made from samples in the market, and therefore more correctly 
represent the general average composition of the manure ; the 
chief difference, however, as above stated, is in the proportion 
of phosphates, and in the determination of the soluble phosphates. 
Now it must be borne in mind that phosphoric acid, whether it 
be soluble from being combined with potash or soda, or in the 
state of soluble phosphate of lime, is of the very highest import- 
ance as manure ; and we ought no longer to omit, in the esti- 
mation of the value of guano, the fact that it does contain so con- 
