246 
SCIENCE. 
1 
of articles* on the subject of cohesion and the atomic 
theory, the latter of which he attacks with all the acuteness 
we are wont to find in his writings. 
In regard to Mohr’s Gesehichte der Erde , which he rightly 
calls : Geology on a new basis , it is impossible to say little, if 
it should be spoken of at all. Suffice it, however, to state that 
it is not what is usually called Neptunism what Mohr advo- 
cates ; it is free from any kind of “ ism,” as the man who 
wrote it himself was. But in thegenerally accepted plutonistic 
geology, fire plays such an omnipotent idle, that any deviat- 
ing view, any appreciation of the true state of things geo- 
logical, is believed to deserve that name from the outset. 
The so-called Neptunism of Mohr has, however, nothing 
in common with the impossibilities of the Old Neptunistic 
School of Werner and his followers. 
There is this radical difference between the views, as yet 
generally accepted, and those advanced by Mohr : 
His aim is to show in what manner the several minerals 
and rocks, composing the outermost, accessible strata of 
our earth, have been formed ; the question of time he consi- 
ders to be not only irrelevant, but also very difficult of as- 
certaining. His firm conviction of the falsity of the nebular 
hypothesis and the previous fluid state of the earth and the 
present molten state of its interior has been strongly sup- 
ported of late, not only by other savants , but by a number 
of facts and reasonings. The foremost among the former is 
embodied in the results of careful measurements of temper- 
ature in the deep boring (4052 ) at Speremberg, near Berlin, 
conducted by the most learned and experienced mining 
officials of the Prussian Government. They show that the 
old supposition of 1" C. increase of temperature to each 
ioo' is fallacious, and that this increase diminishes con- 
stantly in going down. Here is the table : 
Depth. Temperature. Increase per ioo ft. 
700 Rh. ft. 
15 654° Reaumur 
1.097 0 R. 
2.468° 
900 
17 849 
1x47 
2-356 
1100 
19 943 
0.997 
2.243 
1300 
21.937 
0.946 
2.128 
1500 
23.830 
0.896 
2 018 
1700 
25 623 
0.846 
1.904 
1900 
27 3 r 5 
o -795 
1.789 
2100 
28 906 
0.608 
1.368 
339 ° 
3 6 756 
Wnile for the lowest 100 feet it was : 0.445 0 R. (1.001° F.) 
“This would make the final result, as stated by Mohr,” 
says Dr. Klein,* “ very well founded, nay, indisputable, 
viz. : ‘ that the increase of temperature will cease altogether ;' 
not at a depth of 5000' or 6000 , as Mohr will have it, but, 
at all events, at a depth considerably below 100,000'.” 
Thus, in addition to the many astronomical, physical and 
chemical reasons, which are irreconcilable with the nebular 
hypothesis and with the theory of the molten interior of the 
earth, derived from this hypothesis, Mohr has pointed out 
an irrefutable fact which supports this position.** For, 
continuing the slight increase found in a proportionate 
ratio, at the point where there will be no more increase, the 
temperature actually obtaining will fall much below the 
melting point of lead ; this had been predicted by Mohr 
on other grounds, before the measurements made at Sper- 
emberg had been published. 
Chemistry, especially, is ingeniously applied to geology in 
Mohr’s work, and from the chemical constitution and 
physical properties of the various minerals and the rock- 
formations which they compose, conclusions are arrived at 
which throw a new light, in many cases, on the probable ori- 
gin and subsequent metamorphosis of the various compo- 
nent parts of the surface of our globe. l o mention only 
one important result, we may refer to the different properties 
of the Silicate rocks having volcanic origin, as compared 
with those having, until lately, been supposed to have a 
* Lieuig’s “ Annalen Volt 135, 1879 ; pp. 133-213. 
Note. — The rest of this series which the editor of the Annalen de- 
clined to publish, are those mentioned in the fcot-note on p.203 of No. 
17 of this journal. 
* Die Fottschritte der Geologie , 1874-’ 75 ; /. 57. 
** In a future article this subject will be exhaustively treated, and the 
position, taken by Volgek, Mohr and Radenhausen in regard to the nebu- 
lar hypothesis, as well as that 01 Sir William Thomson Poulet, 
Skroup, Stehry Hunt and others in regard to the Earth’s molten In- 
terior, will be thoroughly treated of and criticized. A letter, also, from the 
pen of one of America’s fir;t astronomers will be quoted, in which this emi- 
nent scientist states his views on the subject in a manner which adds the 
additional weight of his superior authority to the evidence adduced agaihst 
this Hypothesis. G. W. R. 
‘ plutonic ’ origin. The several properties which the one 
kind possesses are not found to be properties of the other, 
and Mohr, therefore, takes strong ground to deny their 
fiery origin. 
Among these properties, demonstrating their crystalline 
origin, may be mentioned the following : 
1. That Feldspar, Augite, Hornblende, Mica, Rock- 
crystal, Quartz, etc., as well as the rocks which are com- 
posed of these minerals, all show minute cavities contain- 
ing water which are not found in rocks that have undoubt- 
edly been molten, such as Obsidian and other lavas. 
2. That the specific gravity of the silicic acid contained 
in them is greater (2, 5 — 2, 6) than that in volcanic rocks 
(2, 5—2, 3). 
3. That by melting these crystalline rocks (Basalt, Granite, 
etc.,) their specific gravity is reduced in the same proportion. 
4. That petrified wood, fossils, and other pseudomor- 
phoses of organic origin, and even organic matter unchanged 
(Asphalte in Granite), is found to be enclosed in them. 
5. That the crystalline rocks decay much easier and 
quicker than the volcanic molten rocks. 
6. That many chemical actions, combinations, etc., would 
be impossible if a molten condition was presupposed, etc. 
These and other properties of less importance undoubt- 
edly form a strong array of proofs against the '■plutonic' or 
fiery origin of the Silicate Rocks. 
The formation of lime-deposits takes place according to 
Mohr in the ocean by the following bio-chemical processes : 
The sulphate of lime contained in the sea-water is assi- 
milated by the marine plants ( Algce and Fucus especially), 
and by them decomposed in the course of their vital pro- 
cesses. While the sulphur fenters into albuminous com- 
pounds, the lime unites with carbonic acid, and both go to 
form part of the plant itself. The plants serve as nourish- 
ment to the myriads of minute animals ( Rhizopoda and Fora- 
minifera), which populate the oceans, and while the carbon- 
ate of lime serves to build up their shell, the sulphur is 
eliminated by their bio-chemical process as sulphurous and 
hydrosulphuric acid. These shells which lie from 10 to 15 
feet deep at the bottom of the oceans, are the chalk and 
lime-beds of the future. 
The presence of organic matter in meteorilic masses and 
the absence of carbon in meteoritic iron are pointed out by 
Mohr as further proofs against the plutonistic and in favor 
of the crystalline origin of the heavenly bodies. The chap- 
ter on these mysterious visitors from the celestial spaces is 
the longest and certainly one of the most interesting. 
His views, especially in regard to the constant metamor- 
phosis of rock-strata, are in fair way of becoming generally 
accepted — although his name is not as yet mentioned in 
connection with them.* 
Another theory which refers the formation of coal-fields 
to the deposition of immense masses of sea-weeds and 
tangs at the bottom of the ocean, has been greatly sup- 
ported by the discovery that Iodine and Bromine are re- 
gularly found in the smoke-black from chimneys where 
coal is burned. 
The book abounds in new and original researches 
as well as in bold deductions ; and even those who do not 
agree with the author will find in it an almost inex- 
haustible source of information, and will experience that 
great delight which the writings of a great thinker always 
give to an impartial reader. 
In conclusion, it may be safely said that Mohr belonged 
to those whose writings and the results of whose labors will 
not lose interest as time passes, but will rather be more and 
more generally appreciated. He has said or written but 
very little that he was forced to revoke; on the contrary, 
many of his views have stood against the attack of time 
and of his adversaries, and many of the latter have been 
forced to admit that he was right. 
Personally, as has been mentioned already, Friedrich 
Mohr was the most amiable of men, and the Editor of the 
'Gaea,' Dr. H. Klein, who wasanearfriend ofhisduringmany 
years, rightly says of him (in a private letter to the writer): 
“ In every respect Mohr was a man who would be an or- 
nament to any period of Human History.” 
* Strata of Shales, Mica-Schist, Calcareous Schist and Gneiss not in- 
frequently are so uniformly spread out, in the same locality, that there 
can he no doubt of their common origin. 
