94 OCCURRENCE OF EARTHQUAKES AT DIFFERENT SEASONS, 
From this table it appears that the occur- 
rence of earthquakes in the different seasons 
was as follows : — 
NORTH HEMISPHERE. 
In the three harvest months=10l 
,, winter ,, 98 
,, spring ,, 95 
,, summer ,, 75 
SOUTH HEMISPHERE. 
In the three harvest months=5 
,, winter ,, 8 
„ spring „ 4 
,, summer „ 3 
In reference to the hours at which they 
took place during the same period, we have 
the following data for earthquakes : 
A.M. 
P.M. 
From 12 to 1 o’clock. 
= 15 
6 
„ 1 2 „ 
11 
7 
„ 2 „ 3 „ 
12 
10 
„ 3 „ 4 „ 
14 
13 
„ 4 „ 5 „ 
16 
8 
„ 5 „ 6 „ 
11 
6 
79 
50 
„ 6 „ 7 „ 
= 6 
5 
7 „ 8 „ 
8 
13 
» 8 „ 9 „ 
7 
11 
9 „ 10 „ 
8 
10 
„ 10 „ 11 „ 
18 
8 
„ 11 „ 12 „ 
5 
6 
52 
53 
Total. . . . 
=131 
103 
EARTHQUAKES AT BASLE.— 
According to Professor Merian, the earth- 
quakes at Basle are correctly estimated as 
follow : — 
In the 11th century, 3 
„ 14th „ 4 
,, 15th „ 5 
„ 16th „ 23 
In the 17th century, 59 
„ 18th „ 24 
„ 19th „ 4 
Total 122 
118 occurred in the different months, as 
follows : — 
January 12 
February 14 
March 6 
! April 5 
May 11 
June 3 
July 7 
August '. 8 
September 12 
October 11 
November 14 
December 15 
The most severe earthquakes were on the 
18th October 1356, when 300 persons lost 
their lives ; on the 21st July 1416, 7th Sep- 
tember 1601, and 17th November 1650. 
Compounds of Ferro-cyanodides and Am- 
monia, by Dr. Bunsen, of Gottingen. 
1. AMMONIA FERRO-CYANODIDE 
OF COPPER. — When a salt of copper 
is precipitated by ammonia, and an excess of 
the latter added, so as to re-dissolve the pre- 
cipitate, if ferro-cyanodide of potassium be 
brought in contact with the solution, a pre- 
cipitate is not immediately produced, but 
after standing for some time, or by boiling, a 
brown crystalline substance falls in fine 
scales. After drying, the substance forms a 
brownish yellow mass, which is soluble in 
ammonia, but not in water or alcohol. When 
heated in a glass tube it becomes first blue, 
then purple-red, and assumes a dark colour, 
but gives out no water. By caustic alkalies 
it is resolved into hydrate of copper, and 
ferro-eyanodide of ammonia ; and by acids 
into ferro-cyanodide of copper, and aramoni- i 
cal salt. 
Dr. Bunsen found its composition to be, 
iron 13*20, copper 3033, cyanogen 38'08, 
ammonia 16*14, water 2*25 = 2, 4, 6, 4, 1, 
atoms respectively. This composition may 
be expressed, considering the ammonia as 
occupying the place of water, by 2 Fe Cy + 
2 Cu Cy + 4 N H^^ HO = 76125 the 
atomic weight. 
2. AMMONIA FERRO-CYANODIDE 
OF ZINC, is prepared in the same way as 
the preceding. It is a white crystalline pow- 
der. Analysis afforded for its composition, 
iron 13*15, zinc 32 27, cyanogen 39*04, am- 
monia 1T50. water 4 0 = 2 Fe Cy -f- 2 Zn 
Cy -1-3 NIP 4- 2 HO. 
3. AMMONIA FERRO-CYANODIDE 
OF MERCURY. — The preparation of this 
salt is attended with some difficulty; because, 
ammonia nitrate of mercury dissolves nitrate 
of ammonia when excess of alkali is present. 
When Ferro-cyanodide of potash is added to 
this solution, a yellowish precipitate subsides, 1 
which, when the solution attains its proper 
degree of dilution, settles on the sides of the 
glass, in the form of small, transparent, shin- 
ing, wine-yellow, four-sided prisms. But, in 
order to obtain them, several precautions are 
necessary. The solution must contain as 
little water as possible. The solution must not 
be too much concentrated, nor must the pre- 
cipitation be conducted by heat, because part 
of the mercury wilt be reduced, and the pro- 
duct will have a gray colour. It is best to 
discover the necessary degree of concentration 
by some preliminary trials, — to precipitate the 
compound in a vessel surrounded by ice, and 
then to agitate the solution. A yellowi.-h pre- 
cipitate subsides, from which the supernatant 
liquor is to be removed, and a quantity of 
concentrated ammonia poured over it. As 
long as the salt is impregnated with ammonia 
it retains a fine citron -yellow colour, and 
crystalline structure. By drying in the open 
air it undergoes partial decomposition. When 
treated with water it becomes red. It consists 
of iron 8*58, mercury 59 09, cyanogen 23 74, 
ammonia 5*19, water 3*40: expressed by Fe 
Cy -F 2 Hg Cy 4- NH^ + HO. 
4. AMMONIA FERRO-CYANODIDE 
OF MAGNESIUM, is procured by adding to 
a solution of magnesia salt, ammonia, till no 
further precipitation takes place, and then 
pouring in a solution of ferro-cyanodide of 
potassium. After standing or boiling, a white 
powder falls. It consists of iron 18*86, mag- 
nesium 10*72, ammonia 10*75, cyanogen 56*27, 
water 3.40 = 7 ( Fe Cy + 2 Mg Cy + 5 (Fe 
Cy +2NH3Cy) + 6HO. 
