PRACTICAL ARBORICULTURE 331 
better these trees should be left to grow into good lumber and perpetuate the for- 
ests. There is much wood of no value except for fuel—enough, | should think— 
and the pine should be saved. 
FLOATING GARDENS. 
While the City of Mexico is eight thousand feet higher than sea level, there 
are in the vicinity several lakes and marshy tracts which require extensive 
drainage operations. The Viga canal is one of these drainage systems, and upon 
it are numerous barges, which transport farm and garden produce from the mar- 
ket gardens to the city. Flat-bottomed boats, propelled by a pole, convey passen- 
gers to the Floating Gardens. 
The gardens are located upon marsh land quite similar to the tule lands of 
California. The soil is composed of decayed reed and grass roots, being entirely 
of vegetable mould and quite fertile. Ditches at frequent intervals drain the 
gardens and furnish means of communication by canoes and small boats to the 
larger canal, and thus to the city. Here are the great market gardens, where veg- 
etables are grown for Mexico’s consumption. Here, too, are grown the magnifi- 
cent flowers which form one of the principal attractions of Mexico City, the 
flower market being a wonder in the quantity and exquisite beauty both of the 
individual tropic Howers and the magnificent floral forms, which are made with 
great taste and skill. 
Street cars also connect the city with the villages upon the Viga canal, and 
they are well patronized. 
VOLCANO COLIMA. 
Colima, the only active voleano in North America, was in eruption. Our 
illustration shows the mountain with a stream of vapor rising in an immense 
column. 
I spent one day and two nights at Tuxpan, on the Mexican Central Railway, 
taking many photographs of the volcano and of the country surrounding. 
At night the sudden explosions were accompanied with fire, and clouds of fine 
sand were scattered for great distances, but no lava was seen. The mountain 
has two distinct cones, only one of which is in eruption. The other is called the 
cold mountain. 
The distance from my point of view was about ten miles. I ascended 1,200 
feet upon a mountain near Tuxpan to procure a better view of the volcano than 
could be had from the plain, but during most of the day the clouds gathered and 
hung about the high peaks, 15,000 feet elevation, and seemed to be attracted 
scarce moving for hours. At the same time the sky was absolutely clear in all 
other directions. 
The eruptions are not continuous, but intermittent, occuring several times 
during the day and night. 
Colima is nineteen degrees from the equator and is in view from a point 
within a mile of the Mexican Central Railway station, Tuxpan. 
