The Montgomery advertiser., 1902-05-18
VOLCANOES A PART OF ! ECONOMY OF THE EARTH
EruptiOns Make an Immense Contribution to the ! Land and Add Largely tothe Formation of the Sea Bottom. :

f. tons. entitled, "A Textbook of Geology" by Albert Perry Brigham contains this on the subject of volcanoes:
 Volcanoes make m immense contrinu; ont S; largely to the formation of the sea bot tom by election of fragmental matter. tqndeed. we should not think of volca- A1hoes (and the same might be said of tglaciers) as abnormal or exceptional parts of the economy of the earth. Such 'Imaterial is largely at first in molten state. blown into dust and bits of larger size by stupendous explosions. This Is the origin of the so-called volcanic ashes. which are in no sense products of com 4bustion. but rather of intense, mechanic ally applied energy: So great is the be darkened for hundreds of miles. and the surface of the sea covered for long 4 distances from the seat of the eruption ty-five miles from one of the Nicaraguan volcanoes. and twenty-four miles away the ash fell to depth of ten feet. Dust from an Iceland volcano has fallen in such quantities as to be shoveled from sthe decks of ships near the Orkney and Shetland Islands, while in 17S3 ash from $ the same source fell in Caithness. the northeast county of Scotland. so largely remembered as the year of ''rhe Ashie. 7" If the fragments are of the size of pea and ranging to that Of walnut they are called lapilli. Sometimes huge lava. or of the country rock through which the vent is formed. are hurled to some height and distance. Lumps of molten lava are also cast into the air and ccol while under the influence of rotary motion, assuming. variety of pear shaped and dsklike forms. These are known as volcanic bombs, and vary in diameters from an inch or two to one or more feet.
 l he elected vapor gives origin to pow erfui rains. and the water mixes with the volcanic ash often in in mud mud hows tSs oi esh consolidating in the place where ,t Ar- fallen. makes the volcanic rock as tufa. of which there are exten-
 rn,ations in some volcanic re-
 yriter gives concise history Of .-H s, Etna, the Hawaiian volcanoes,
 a ssen snd As ss' to S0isnsss tss ssuss. 'a tss l... ction the author says: C.
 That Causes Explosions. :. inclusive word has been spoken
 ,- subject final conclusion may
 md the bounds of human inves-
 .r As with the glaciers the }. earthauakes. or the origin or many facts are known, and some
 ,.r conclusions cannot be doubted. but sr. nate cause yet lies in obscurity. -r not discouraging to the true stu q t only one of many proofs or the ll, r- m of our kowledge.
 rv- uestions must he asked:i O What f~ra .' sources of the heat neededfto 2 u e. rocks and form the gaseous If vast extent? @ What is the fr lat expels these materials from
 st? As regards the first. mary
 have been given which must 're e, or at least appear to be ir.- > Volcanic heat has. been
 to be remnant of the origina'
 the globe. But on this theory
 1 seem that vulcanism~ should a.ys u. geological history. This has not been proved, and some facts look in the opposite direction Others have thought that the heat comes from powerful chemical reactions in the deep 'natura al laboratories of the earth's crust But this cause seems insufficient for the known that rocks melt and become pias- tic under great pressure, in the presence i of water and alkaline materials. Fhis IS called aquco-igneous fusion, but does not account for the great heat of volcanoes. All these causes may contribute to the result in various degrees and localities. the original heat If the earth is be- neved to hold the rocks of the crust near the melting point at no great distance below the suface. Such crushing as goes with mountain making may add heat enough om mechanical origin to Cause frsion. A seemingly paradoxical theory is that the under rocks would melt if they were not under stupendous pres- sure. and when at some points this pres sure is relieved in the succession or strains which the crust undergoes the rocks there pass into a molten state. The two theories are not inconsistent. At one point we have added pressure and added heat; at another. removal of pres sure and lowering of the melting point.
 As to the cause of explosion, the an swer is hardly more satisfactory. The sudden conversion of water into steam Is thought to have much to do with ex- plosive eruptions. and the more as most volcanoes are near the sea. But this does not account for inland or quiet eruptions. 3- : tn could reach the seat of the heat. either by saturation or sudden inflow. Chains of volcanoes as in the Andes, corre- spond with lines of mountain making. perfect theory must explain all the facts. Why are some eruptions quiet and others violent? Why the differences in the composition and heat of lavas? Why should there be a difference of 10000 feet in the height of the lava columns in the adjacent volcanoes of Mauna Loa and kilauea? Why are some vents in termittent and others constant in ac- tion? Such are some of the questions No theory covers all of these.
 'The Storied West Indies," by Fred erick A; obSrL is another lttie ,o noos considerable space is devoted to the vol canic chain in the West Indies. Each island saws the author. 'is a partly submerged volcano, its sides. and even the extinct crater clothed with luxuriant growths Although there are several outlying islands, such as Anegada, Saint Martin and Saint Bartholomew. the real chain of volcanic isles begins with pair of peaks belonging to the Dutch. named Saba and Saint EustatiuS.