2. THE EARTH

Astronomists and geologists agree that this universe suffered a great conflagration about 2,000,000,000,0000 years (two thousand million years) ago. Umbgrove (1942) has dealt with these and called allied matter in his book The Pulse of Earth.¹ Our planetary system seems to have originated in this epoch and, according to all probability, the earth, together with the other planets, was torn from the sun. It must have had a very high temperature at the time of birth. It is probable, but still uncertain, whether the moon was torn off from the still plastic earth.

Studies of meteorites have taught us that the abnormally high specific gravity of the earth (5-6) is probably caused by the nature of the core, which should be a nickel-iron alloy (according to some it might be highly compressed by hydrogen!). Now from the propagation of earthquake waves we know that there seems to be a discontinuity at about 3,000 km depth. There is another at a depth of 1,200 km. Now Goldschmidt (1922) assumes that during the cooling of the incandescent earth, an enormous metallurgical process took place, in such a fashion that the regulus, the heaviest core, attained the deepest position, this surrounded by the ‘stoma’ a region called chalcosphere, containing sulphides and oxides, further surrounded by the ‘slug’, called eclogite.³ The outer 120 km or so is the light silicate mantle (for densities see Fig. 2.1). The most precious substances, the heavy metals, only occur occasionally in the outer shell. In this silicate mantle the lighter Al silicate (sial) float apart upon the heavier magnesium silicates (sima). There was, therefore, first a separation by gravity; according to Goldschmidt items of similar radius could take each others place in a crystal lattice. This accounts for the recurrence of many substances in minerals.

Most of the oxygen was used up in the formation of oxides. If the core had been exposed only a small amount of its sima could have been oxidised, as even all of the oxygen present would not have sufficed! So, the earth outer crust is chiefly oxide, it dictates the composition of the lithosphere. The original atmosphere has no oxygen, the hydrogen, while abundant was slowly but surely removed from the atmosphere, as the gravitational field is too weak to hold it. Lighter gases left the earth, only those in the neighbourhood of M.W. [Molecular Weight] 14-18 (nitrogen, oxygen, water vapour) being permanently fixed. Much later, when the earth’ crust was permanently fixed, water vapour began to condense.

The partition between land and water as we know it now, is probably very old. The theory of continental drift, proposed by Wegener, has been largely abandoned by now. Orogenic period, glacial period and epochs of increased volcanism occurred rhythmically (see Umbgrove, 1942, The Pulse of the Earth). Geobiologically important is the hypothesis of Holmes,⁴ according to which the level of the ocean over the entire surface has risen ±40 m since the last glacial epoch. North Sea, Java Sea and many other shallow seas originated since the last glaciation by melting ice. Of undisturbed rock there is very little on the continents. On the ocean bottom, according to Escher, the sima is coming to the surface.

We live on the cover of a great crucible of which the valuable core cannot be reached. Only traces of heavy metal contents penetrate into this outer shell. The gravitational differentiation and affinity for oxygen have made these things to pass. The nitrogen has almost quantitatively passed into the atmosphere, which is a shell of gas as much as the gravitational field of the earth will hold. The hydrogen escapes; CO₂ and oxygen are better represented on the lower atmosphere. Therefore, only a thin shell is habitable.

The earth is not a perfect sphere, but according to the ideas already developed by Laplace, flattened at the poles, a so called geoid. Apart from the difference in the acceleration of gravitation going from the pole to the equator, we find local disturbances in gravity. These may be due to penetrations of heavy material or, to printing in of lighter material. Movements on the earth’s crust tend to equalise these masses in order to equalise the forces. This is the principle of isostacy. Due to the difference in specific gravity of sima and sial, the deviations in gravity may vary. Over the oceans there is usually a deficiency, over the continents an excess. Isostacy also requires heavier material under the oceans. Here the sima comes to the surface (B.G. Escher).⁶ The ocean floor is, therefore, lithologically different from the continents. This has little bearing upon our problem, however, as the biotic condition at abysmal depth is derived from the same superficial strata.

Vening Meinisz has measured the acceleration of gravity by means of a pendulum aboard a submarine over several oceanic tracts, particularly near the Dutch East Indies. His results combined with those of recent oceanographic expeditions (Snellius, Meteor), warrant the conclusion that excesses and deficiencies in gravity go hand in hand with zones of maximal seismic and volcanic disturbances. To account for these deviations a buckling of the sial has been assumed. This has been made probable by the beautiful experimental work of Ph. Kuenen.⁸ This downfolding and wrinkling (so to say) has determined the face of the earth crust (Fig. 2.2). Orogenesis has been performed this way (Umbgrove, The Pulse of the Earth) and subsequent weathering has brought down the mountains to their present level. We have, therefore, a geoid with variation from sea level of ±10 kilometres. This determines the “stage of the life drama”, with its variation from ¹/₁₀ to 1000 atmospheres pressure, with oxygen pressures varying from ⅕ to zero.⁹

According to Alfred Wegener the continents, which were originally joined have, when the earth’ crust became stabilised, began to wander and to draw apart. South America fits snugly into the “armpit” of Africa, even a lithological continuity could be found here (J. Dutoit).¹¹ So N. America has drifted from Europe. The pole also, has shifted its position materially so, that, climatologically, the occurrence of Ginkgo and other fossils from moderate climates could be accounted for. This very ingenious hypothesis has influenced biology, and in particular biogeography, considerably, although on closer inspection, it does not seem to account for the facts. Several tertiary florae of moderate character occur over the same ground circle of latitude, showing that the pole has kept about its position. Also, the wandering continents seem, in view of recent geological work, increasingly improbable.

Oceanic currents originate through differences in temperature and salinity, or of the density of the water. The origin of the one well known current, the so called Gulf Stream, is given below. Polar ice causes a vertical water movement downwards; tropical insolation causes a vertical movement upwards. These two vertical movements are closed into a circuit - superficial water flowing towards and abyssal water away from the pole (Fig. 2.3).

Geobiologically ocean currents are important for:

1) Vertical currents change the condition of Colby;¹²

2) They often bring fresh minimum elements;

3) Horizontal currents are important vehicles (katadromic and anadromic fish, eels, Joh. Schmidt);¹³

4) The influence of a warm or cold superficial stream influences climate profoundly, as in Europe, or the cold Japan stream in California.

Temperature, gradients and rotational velocity of the earth are the prime causes of the currents (Fig. 2.4). The high altitude current from equator to pole is akin to the heat expenditure oceanic current. The stratosphere winds heading W-E is caused by the earth rotation. From W. Humphreys’ book Physics of the Air brief statements should be taken as to the origin of the principal winds.¹⁴ Monsoons are caused by insolation of land masses and the rising air engendered thereby. Troposphere winds are geobiologically the most important. They act as distributors of latent life, they also, together with oceanic currents, determine climate. The vertical air currents may carry up objects to such a level that they reach the rotational circuit and are thus transported once or several times around the earth before they settle (see Section 4.2). Winds have a great influence upon evaporation; also, the height of a tree is not determined by the properties of water, but by the average wind velocity (wind velocity may be as high as 200 mm/sec).

See further Section 4.3, Distribution, Cosmopolitans, Physical Causes. Fig. 22 ‘Verbreitung des Aschenfalls des Katmai’ from Barth (1939, their Fig. 4.11a).

The earth radiates as a black body of ±288 °K. Temperature may vary, at the surface, from ±80 °C on black, insolated rock, to -60 °C near the cold pole of Verkhoyansk, Siberia.¹⁵ On the pole the Antarctic is colder than the Arctic, because the earth is in aphelion during the Antarctic winter. The earth keeps its surface temperature because of its atmosphere, which efficiently blankets the entrapped solar heat. Celestial bodies without atmosphere like the moon, show extreme (+150 to −100 °C) diurnal temperature variation, which makes them misfit as an abode of life. The earth temperature is further regulated by the physical properties of water. The high specific heat of the substance makes it a veritable accumulation of heat, its high heat of melting (-80 cal) and heat of evaporation (+580 cal at 15 °C) make the surface of the earth despite minor fluctuations, a veritable thermostat. Temperature records throughout the year should be given to illustrate the small differences between tropical and subtropical climates (e.g., from Humphreys). Temperature also determines the amount of water vapour the air may earn, and of course, also determines its density. The temperature factor is therefore, the most important in the physics of the atmosphere. The rivers and lakes, but more experimentally the ocean, vary much less in temperature, which the soil is still more conservative. Deep sea temperatures vary around 2-3 °C, deep freshwater lakes, of course, show the temperature of the maximum density of freshwater 3.98 °C. While in soil the “troposphere” (influences of weather) penetrates only 10-20 metres in water this sphere (epilimnion, tropolimnion) may be more than 100 m in thickness. Below that level, in soil, the temperature rises about 3 °C for every 100 m, so that, theoretically at a depth of 1,500 m, there should be an end of active life.

N.B. This diagram should be corrected and amended with the aid of existing literature.

See also Section 5, for the oceanic and limnological condition.

According to Goldschmidt, the following elements are typical for the various zones described in Section 2.1.5 and on Figure 2.1 of this treatise. The core is siderophilic, the next layer is called chalcophilic and the outer layer is the atmosphere (Table 2.1).¹⁶

In the siderophilic zone there are 7/19, in the chalcophilic 8/26, in the lithophilic zone 21/54 biophilic elements, or 0.37, 0.31 and 0.40 of the total (Fig. 2.6).¹⁸ The biosphere bears, therefore, no special chemical relation to the outer crust. From the atmospheric elements, however 7/14, or 0.50 show affinity. This might indicate that, apart from lithophilic H, the biosphere has been derived in part at least from the atmosphere. As compared with other celestial bodies, the earth is rich in iron. The oxygen in the outer shell would not suffice to oxidise the native iron of the core. After the various layers, like in an iron smelter, had separated, the temperature, according to some was too high even for oxides to form. Experiments with the electric oven have shown that at those temperatures, silicides, nitrides and carbides would form (Lénicque, 1903; cited by Clarke, 1916, p. 57). At lower temperatures, however, the oxygen began to combine. Nitride of iron, still exists in volcanic exhalations, but most of the nitrogen remained uncombined in the atmosphere. The oxygen must have been utterly depleted. Water was formed, and the original atmosphere should contain carbon dioxide, nitrogen, water vapour and volcanic hydrogen. Then the process of weathering began, by mechanical action of water, as vapour, then as liquid, much later as ice, and the weathering influence of carbon dioxide besides. Salts and silt are disintegration products of the eruptive accumulated in the primitive ocean. However, the early attempts of Halley (followed in modern times by those of Clarke, 1916),¹⁹ to account for the composition of the ocean by rock leaching only, should fail, because of the preponderance of sodium over chlorine in eruptions, while in the ocean their concentration is similar (Correns, 1939).²⁰ It may be that the chlorine in the ocean is for a large part at least of volcanic origin.

The elements of the earth crust are almost all of low atomic weight (Fig. 2.7). The economically important, heavy metals being accumulated in the core in the regular shell. The shell is preponderantly of eruptive characters, the sediments forming only ±5 % of the 10 mile outer crust, of the lithosphere, roughly three quarters is represented by aluminium silicates, the other metals appearing only as a sort of cementing substance. Following in importance is water, on the total ±9 %. Carbon, for our consideration the most important element, only has a frequency on the entire crust of 0.18 %.

Only those elements that are geochemically “mobile” are of interest for our problems. According to Vernadsky (1924, Geochemistry) all of the crustal elements enter into a cycle. As an example, we take the iron (Fig. 2.8). Processes surrounded by a line are biological.

The outer shell of the earth is an oxidised shell, although a great many substances are in a reduced state, the overwhelming majority are present in the highest oxidation stage possible. Notable exceptions, of course, form sulphides in the magna, further such substances as CO and H₂ on volcanic exhalation, ferro-salts and ammonia, nitrites, sulphites etc. The reductive processes in the sedimentary layer of the lithosphere and the hydrosphere are probably entirely biological. It is the biosphere, and in the biosphere the plant cells, which function as the great reducing agent, for the oxidised environment.

See also Sections 3.8.12, 3.12.1 and 3.12.2.

Due to the oxidic character of the outer shell it seems plausible, like Correns (1939) does, to write the equation of a compound like glauconite as K₂(MgO.FeO)Fe₂O₃ Al₂O₃ 8 SiO₂ 3 H₂O.²¹ Such an equation stipulates the oxidic nature of the lithosphere sufficiently, no less than 7 different oxides in a combination of 17 oxides being present! Nitrogen alone is geochemically too inert to react, except at very high temperatures (nitrites in volcanic exhalations), but living cells are able to attack nitrogen as well. Not only the metals but also the other substances are found chiefly in the highest oxidation state; carbon as CO_2, sulphur as sulphate, phosphorus as phosphate, nitrogen as nitrate, silicon as silicate. Oxygen pervades therefore the entire outer shell of the earth, reducing thereby, in the majority of cases, the energy potential of the substrates to a low level.

Apparently, the earth crust contains chiefly the lighter elements. Oxygen is by far the commonest; it not only pervades the outer shell, but also reacts with almost all other elements. For the oxidation of the central core of the earth however, our atmospheric oxygen would be insufficient. The commonest substances on earth are Al₂O₃, SiO₂, Fe₂O₃ and H₂O. Most of these substances only represent phases in a cycle, however. Such a cycle is illustrated diagrammatically for the iron. It is mentioned that only plant cells are capable of reducing the outer environment, thereby setting up a certain energy potential necessary to contain life of plants and their dependents: the animals.

Geobiology is concerned with the outer shell of the earth, taking into account the deepest oceanic depth. Therefore, a shell, about 10 miles thick (16 km) has to be considered. The solid crustal matter we call the lithosphere, the thin larger of liquid in it (ocean and freshwater) the hydrosphere, while the gaseous envelope, the atmosphere is weakly held by gravity (Table 2.2).

In the table the relative importance of those shells is given. The biosphere, the thin film of green space spread over lithosphere and pervading the hydrosphere, cannot properly be estimated. It would only amount to a very small correction in the above figures, however. Although quantitatively unimportant, this essay tries to show the great influence of the biosphere upon earth.

Max. equivalent to 1,268,000 cubic miles of water, its composition, according to Sir William Ramsay is together with other substances in small amounts, such as H₂S, H₂, NH₃, HNO₃ benzene, dust, organic remains and, of course, water vapour.²³ The other rare gases krypton, xenon, helium and neon are present in very small quantities. Carbon dioxide is always present in small quantities. Although this gas is so much active in the earth’s metabolism the percentage is remarkably constant (0.02910 – 0.03027 % by volume). The oxygen varies also little, the atmosphere is slightly richer in oxygen near the poles (variation from 20.720-21.180 vol. %). By electron discharge, oxides of nitrogen may be found, yielding nitrous and nitric acids. “All the nitrogen of organic matter came originally from the atmosphere” (Clarke, 1916). Hydrogen always occurs in the atmosphere, in varying amounts (1:5,000 max). SO₂ also occurs in the air, probably an industrial contamination chiefly. The carbon dioxide in the atmosphere amounts to 2.2 × 10¹² metric tons, corresponding to 6 × 10¹¹ tons of carbon. A city like Paris generated, in 18,443 × 10⁶ m³ CO₂ daily. The annual consumption of coal (±2 × 10⁹ tons) adds to the atmosphere, therefore, no more than 0.001 of its CO₂ addition of CO₂ to the atmosphere is possible through the combustion of carbonaceous meteorites. Much CO₂ is taken up by the weathering of rock (e.g.,  orthoclase from kaolin) according to T.C. Chamberlin, 10⁹-10¹⁰ tons of CO₂ are withdrawn annually from the atmosphere, by rock weathering and by carbon dioxide assimilation of green plants.²⁴ The water vapour in the atmosphere is of course variable and requires special treatment (see Section 5.10.4).

Mass of the 10 mile rocky crust: 1,633,000,000 cubic miles, max density 2.6 is magnetic (see also Section 3.8, Salts and Inorganic Substances), chiefly a rigid crystalline structure, according to Barth (1939, after Goldschmidt) an oxygen lattice held together by cations. Oxygen has, with potassium the largest atom!²⁵ It has often been neglected by mineralogists, but if we plot the frequency not of mass, but of volume, we arrive at most interesting results! (Table 2.4)

Question atom radii are different from ionic radii. How did Barth (1939) get them mixed up?

At first sight it looks as if, when we consider volume, the bioelements should gain in importance as the sequence becomes O-K-Na-Ca-Si-Al-Fe-Mg. However, the atomic ratio of other bioelements is quite small (C = 0.16, N = 0.14, P = 0.35 and S = 0.33 Å apparently). As volume elements they would recede even further down in scale! However, the role of the elements named by Barth (1939) is enhanced. Tables 2.4 and 2.5 on the composition of the elements in the lithosphere, were taken from Clarke (1916, Data of Geochemistry, p. 33). A rough estimate shows that 95 % of the lithosphere consists of igneous rock, 5 % of sedimentary (Table 2.6). Of the sedimentary rock, 4/5 is shale, and the remainder, the amount of sandstone is about here 1/5 times that of limestone. Weathering is, therefore a superficial process. Of the outer shells, the lithosphere occupies 93 %.

Its average composition, in terms of elements, is again given below (Clarke, 1916, p. 35). (The sequence is that of the average for all spheres, including atmosphere and hydrosphere). Bromine for instance is a typical hydrospheric, nitrogen an atmospheric, element. The outer shell, the lithosphere, which concerns us is rather poor in bioelements. Taking the chief ones O, H, P, N. S, Ca < K, Fe, Na < Mg, we see that they practically all are “high” in the scale (among the 20/92 highest). Their average number is 9/92, taking the bioelements in the widest sense, including Mn, Al, Si, Cl, P, Sr, F and moreover Cu, Co, Ni, Mo and V we still see that the overwhelming majority of the bioelements lies among the common elements. We shall deal with this matter more fully. The change from eruptions to sedimentary shall be dealt with in Section 4.3, based on Correns (1939). There also soil formation will be considered.

Water may be vadose (or meteoric) or juvenile, coming from the magna. In the biosphere we also know metabolic water, which originates from combustion of organic substance. The meteoric water is cyclic and is almost quantitatively present in the ocean. The freshwater does not influence it much, but annually there is contribution from the rivers to the ocean, both in salt and in silt. In 10⁶ metric tons, we give Karsten’s estimates of annual contribution of the rivers to the ocean (Table 2.7).²⁶

It may be assumed that most of the carbonate, sulphate, calcium and nearly all of the iron, aluminium and silica precipitate. Furthermore, the rivers concentrate silt to the ocean. Humphreys and Abbot (cited by Clarke, 1916) estimate the annual amount of silt contributed by the Mississippi at approximately 370 × 10⁶ metric tons. The Nile contributes about one seventh of this amount.

Murray estimates the total rainfall at ±30,000 cubic miles; approximately 3 × 10⁹ tons of drainage are carried to sea. Waters from crystalline feldspathic rocks show a high amount of Na and K, low concentration and a high amount of SO₂. Water from sedimentary regions, especially in limestone areas, shows a high proportion of Ca and Mg. Acid waters occur wherever there is organic matter together with very low concentrations of minerals and further in volcanic regions or where sulphides oxidise by bacterial action. But as spring water starts its travel to the ocean, its composition changes on the way. It may meet other wells, it may traverse regions of drainage or irrigation, industrial and domestic pollution may all show their influence. In this essay we shall revert to this problem several times, enough to state that usually the river water is characterised by preponderance of Ca²⁺ and HCO₃-, while in the ocean water Na⁺ and Cl^- predominate in the series (Table 2.8).

The volume of the ocean is about 300,000,000 cubic miles (1,286,000,000 cubic kilometres). The composition of oceanic water is remarkably constant. The following Table 2.9 is from Wattenberg (1938),²⁷ gives the composition 19 ‰ Cl or 34.33 % salt (Knudsen equation, see Section 3.13.3).²⁸

Cation meq 0.5904; Anion 0.5943 ????

The surface waters are always oversaturated with CaCl₃. A great number of minimum substances occur in seawater, which are given in Table 2.10 in 𝛾/L [= 10^-6g/l].

The ocean cannot, as has repeatedly been tried, be considered as a rock leach product, however as Na and Cl appear in quite a different proportion as found in the rocks. The same is true of boron. Perhaps part of the chloride is derived from volcanic action. The attempt to derive the age of the ocean from the accumulation of NaCl seems therefore futile. Apart from freshwater and seawater we meet with solutions of higher salinity; the brines, as an abode of life they represent various remarkable extremes. When we take the ions Na⁺, K⁺, Ca²⁺, Mg²⁺, Fe²⁺⁽⁺⁾, HCO₃^-, CO₃^2-, Cl^-, SO₄^2- and SiO₃^2-, we may build a great number of these really possible solutions, only part of which are realised in nature. Nature therefore, as a butler, only provides the biosphere with a limited number of drinks (see also Section 3.1). We shall see that this terrestrial milieu is always more limited as the potential milieu. Several organisms find their optimum in a liquid laboratory milieu, which is not present in nature.

The annual yield in organic matter (in land as well as in the ocean) may be estimated roughly as 1 ton/hectare 1 Ha = 10⁸ m², the earth is 5.12 × 10¹⁸ m², or the yield in organic matter should be 5 × 10¹⁰ tons, or more than all the river water moving to the ocean! Of this production we put 2/3 on plankton and its derivatives, and the remainder on grassland and forest and their derivatives (animals). Here we do not take into consideration the large beds of kelp²⁹ or the bacterial action in soil and sediment, nor do we estimate human activity entirely from the rest of the biosphere and coin a new term “anthroposphere”.

In the foregoing a very brief survey is given of the composition of the atmosphere, the lithosphere and the biosphere. Certain substances are common to all spheres, to wit water and carbon dioxide. They are of the inorganic world, as well as of the organic, the central substances. In the lithosphere we meet further SiO₂ and aluminium silicates in the hydrosphere sulphate and sulphide and oxygen. In the atmosphere oxygen and nitrogen. A natural division of different types of water does not exist, the usual classification (Palmer, 1911; Clarke, 1916) is cumbersome.³⁰ It may be more logical to classify the water according to pH as the solubility of many substances is a function of the H⁺ concentration (Table 2.11).³¹

Vehicular substances. The earth with its two major dictating influences; gravitational field and incident radiation, enables water to occur in the liquid phase. Water is a most unusual substance and it will take a part of a book to describe its properties, which make it such an ideal substance. Let us call it a vehicular substance; it carries substances in solution, and in colloidal solution. It is the medium of chemical reactions. It is the medium of life. It’s dielectric construct, it’s dissociation, it’s thermal properties make life on this planet possible. The question arises whether there are other possible substances which may act as vehicular? Both E.C. Franklin, the creator of ammonia chemistry, and Lawrence Henderson have answered this question: There is another, but probably not more than one other, such substance: liquid ammonia.³²

A vehicular substance be HV, as compound:

in the case of liquid ammonia, which is, at -70 °C (or at room temp., 90 kg pressure) highly ionised, we get:

Franklin has given us (1932) an ammonia chemistry, which logically proceeds, parallel to the aqua chemistry, to chemical reactions and compounds.³³ For instance, in aqua chemistry carbonic acid is:

Liquid ammonia is an ideal solvent, almost like water. It is highly ionised and takes part in reactions like water does, at -60 °C reactions go with fairly great velocity. So, the low temperature does not inhibit the reaction too much.³⁴

Now if a vehicular substance exists on another planet, it may be that life could also occur there. J. Russell of Princeton has given (Nature, 1939) a description of planets chemical conditions.³⁵ Only these planets should be considered, Mercury being too near the sun, Saturn, too far off. The most interesting fact that Russell reports about Venus is that its atmosphere contains oxygen. Now if Goldschmidt’s hypothesis (Section 2.1.2) about the origin of atmospheric oxygen be true, all of this gas should be derived from the photosynthetic decomposition of water, as in the atmosphere of the cooling earth no oxygen occurred, all of it being fixed in the oxides of the stony crust. If the temperature on Venus is not too high (clouds of water vapour, which are reported, may affect such a screen) and Goldschmidt’s hypothesis be acceptable (which to the author it is), there is no reason why Venus should have behaved differently – and there is therefore no reason why no life should occur on Venus (H₂O vehicular substance).

Whether or not the canals “exist” is still an open question. The white polar spot, which partly disappears in summer, is indicative of melting ice, oxygen and water vapour have been demonstrated in the atmosphere. The same experiments as given about Venus pertain here. Older astronomists report the presence of chlorophyll (leaf green) on Mars! In a written communication to Prof. E. Hertzsprung of Leiden,³⁶ Russell declares that even by means of modern telescopes chlorophyll could not be demonstrated with any degree of certainty. Therefore, we have to rely on the indirect evidence of the oxygen. At least two other planets, besides the earth, show therefore evidence of being inhabited! If we include the possibility of other vehicular substances, we have also to take into account the conditions on Jupiter.

Here there seem indications of absorption bands of methane, nitrogen and ammonia. As the surface temperature is low, methane and ammonia are both in the liquid state. Now methane is a very inert liquid indeed, being a paraffin and as such unlikely to be active as a vehicular substance. But as we have seen, liquid ammonia has many characteristics in common with water. It has a high dielectric constant, it is considerably dissociated into ions, it seems an ideal solvent for both inorganic and organic compounds. Its thermal properties are less extreme than those of water, but still, these would be sufficient thermostatic actions. The possibility of an “ammonium life” on Jupiter, if the solar energy should suffice, should be reckoned with.

Even if we accept water being the only vehicular substance for life, at least two other planets, Venus and Mars, show the presence of oxygen in their atmosphere. The oxygen may only have originated in one way, namely by the decomposition of CO₂ and water either under the influence of sulphate or by other (chemical) means (see Section 3) If we allow for other possible vehicular substances (about which biological experimentation is unfortunately lacking), Jupiter has to be considered as well. The problem about the habitability of other planets is an old one, but it has received new impulses from three sides,

• primo, the spectroscopic observations of Russell,

• second, the oxygen hypothesis of V.M. Goldschmidt and,

• tertio, the creation of ammonia chemistry by E.C. Franklin of Stanford University.

(Kluyver, ’s Levens Nevels, 1937).³⁷

Some great man (“Darwin”) has said “it is mere rubbish to speculate on the topic of life, one might as well speculate upon the origin of matter.”³⁸ The latter has been done and abundantly and it has been, as far as the author is aware, no rubbish. Let us see what may be said about the origin of life upon this earth. If water was the vehicular substance the temperature should have been below 100 °C. There was hardly any oxygen in the air, only CO₂, hydrogen and so much water vapour that there was hardly any sun. Do we know of organisms that are capable to live under these conditions? A great many bacteria are able to assimilate CO₂ by means of hydrogen. This reaction is weakly exothermic (3,000 cal):

The sulphate reducing organism, Sporovibrio desulfuricans,³⁹ still a cosmopolitan, may perform this feat. Such an anaerobic autotroph might have been the beginning of things which much later, when light shone, photosynthesis made its appearance, perhaps with other bacteria-like things like the purple bacteria and the bluegreen algae. The purple worked according to:

and the bluegreens:

Here the oxygen was being developed. So, any hypothesis that starts with a non-chemosynthetic, aerobic organism as the initiator of life on this planet, does not take into account the geochemical evidence at hand. These exist a number of “borderline” organisms, too small to be observed (virus, phage etc.). As they are probably not even organisms, but in any case, that they have always to parade when the origin of life is mentioned, is beyond the author’s understanding.⁴⁰