September 1, 1888.] 



♦ KNOWLEDGE ♦ 



251 



'Washington could do notliing of the least worth with the 

 26-inch telescope, nothing original at all — except the dis- 

 cover)' of an impossible third satellite of Mars, which would 

 make old Kepler turn in his gi-ave if only astronomers 

 would accept it. (They ai-e about as likely to do so as to 

 believe in a total eclipse of a half-full moon.) Every 

 American astronomer worthy the name has been interested 

 in the great telescope, and delighted to do anything in the 

 way of suggestion or aj-sistance to develop its chances of 

 success. 



But the Ti-ustees of the Lick Observatory- have had a 

 .sudden surprise, which might make them unwilling to 

 accept in future the assistance or advice of students of 

 science were they not able to form a tolerably clear idea 

 of the exceptional nature of the man they have to deal with. 

 Mr. Holden has sent in a claim for six thousand dollars 

 for his advice — " services rendered " he puts it. As the 

 Trustees justly point out, if all the rest of those who have 

 helped valued their services at the same rate, the Trust 

 wouhl be bankrupt. They therefore disallow his claim, 

 setting aside 10,000 dollars (from the sum they were pre- 

 paring to hand over to the I'niversity of California) to meet 

 the possible expenses of legally resisting Mr. Holden's suit. 



The Trustees of the Lick Observatory believe that Mr. 

 Holden will withdraw his claim. And very likely he will 

 — if his legal advisers tell him he has no chance of getting 

 the money. But whether he withdraw it or not, he can 

 never remove the disgrace which his claim has brought upon 

 science; for a position has been given to him in the world 

 of science — not by any scientific work which he has done 

 (for he has done none of any value), but by the mistake 

 which learned bodies, in England as well as elsewhere, have 

 made in conferring distinctions on him which in some cases 

 they declined to bestow on fellow-countrymen of his (the 

 late Dr. Henry Draper, for example) incomparably his 

 superiors. I repent me that I did not, when, I fear, it was 

 my duty to be outspoken, prevent, as I could most surely 

 have done, his election to the foreign associateship of the 

 Eoyal Astronomical Society, a body which must now in 

 some degi'ee share the disgiace which Mr. Holden's claim 

 has brought upon all scientific bodies with which his name 

 can in any way be associated. 



THE EARTH'S UNRECORDED PAST. 



EGARDING our earth as a member of the 

 solar system — the chief member of that 

 set of so-called terrestrial planets which 

 form the sun's special family — the astro- 

 nomer studies her witli special interest as 

 the one planet which can be thoroughly 

 examined. The work of the geologist 

 becomes on this account especially important to the .student 

 of astronomy. He does not require, indeed, to have that 

 detailed knowledge of geological matters which is essential 

 to the student of geology ; but, on the other hand, he 

 requires a much fuller and at the same time more exact 

 knowledge of geology than many imagine. He should 

 have, in fact, the same sort of knowledge of geology that 

 Humboldt had of astronomj' — a knowledge sufficient to 

 enable him to weigh and appreciate the theories as well as 

 the facts of a science which, though outside his special 

 domain, so closely adjoins it, that without such knowledge 

 the study even of that special domain of his must be im- 

 perfect. Fortunately the exact study of one department of 

 science, though it cannot help in itself to enable any one to 

 come to sound conclusions in rt gai d to another, yet surely 



protects him against the risk of forming unsound or pai-a- 

 doxical theories, for he knows from the study of his own 

 science what is essential to the formation of just opinions in 

 another. Hence the student of astronomy sees that he 

 must study the results of the labours and researches of 

 geologists thoroughly, though generally. He h;is to take 

 only a bird's-eye view of geology, but the view must be 

 taken from a propei' standpoint, so that no illusions may 

 affect its general accuracy, and, moreover, the surve}' must 

 be complete, not partial. 



Let us see how the astronomer is led to study the geology 

 of the earth. 



We recognise our earth as having in the beginning of her 

 career passeil through that suulike state whose general 

 conditions we can study in the sun. Doubtless there were 

 important ditferences of detail, due chieHy to the immense 

 inferiority of the earth in point of size and mass, just as 

 there are important differences between the first stages of 

 an oak's life and the first stages of the life of a fuchsia, 

 between the beginnings of the life of a fly or a bee and those 

 of the life of a lion or an elephant. Still, in all its more 

 general characteristics the conditions of our earth in the 

 earliest stages of her existence as a separate orb were the 

 characteristics of a sun. The greater portion of her mass 

 must then have been in the vaporous state, even the 

 stubborn metals adding their vapours to the complex atmo- 

 sphere which, in reality, formed then the largest portion 

 alike of her mass and of her volume. Movements akin to 

 those which are taking place all the time in the sun, as well 

 as disturbances akin to those which from time to time alter 

 the aspect of his photosphere, must have taken place in the 

 earth when she was in the sunlike stage of her career. 



Later, after millions of years indeed, for it is by such 

 periods we must measure the lift-time of a world like our 

 earth, large poitions of the matter which had been vaporous 

 became liquid, and eventually solid. It would be more 

 correct, however, to say that as time progressed a larger and 

 larger proportion of the materials forming the earth's mass 

 became liquid, and a larger and ever-growing proportion 

 solid. For just as even at this day not a single drop of the 

 waters of the sea is permanently liquid, not a cubic inch of 

 the polar glacial masses permanently solid, 'so must it have 

 been in the earlier stages of the earth's career with the 

 molten materials formed by cooling from gaseous matter, 

 and with much, at any rate, of the solid materials formed 

 by cooling from molten matter. There must have been 

 continual interchange of condition between the solid, liquid, 

 and vaporous states in the case of neaily all the elements 

 and compounds at first, and of the greater number of the 

 elements, until a great advance had been made — which must 

 have required many millions of years — to the sfcite of 

 matters existing now, when oxygen and nitrogen are the 

 only elements free in cosmically large amount, and water 

 the only compound substance which is free to assume in 

 large quantities the vaporous and solid states, in addition 

 to its customarily liquid condition. 



The progress of the earth through the second important 

 career of her life as an independent orb was doubtless 

 characterised by a steady diminution on the whole of the pro- 

 portion of vaporous matter in her mass as compared with 

 liquid and solid matter, and of liquid as compared with solid 

 matter. There must also have been a steady diminution in 

 the number of substances present in large quantities ani/- 

 vhere in the vaporous form. In an early part of this stage 

 of the earth's career the metals and metalloids would for the 

 most part either solidify or enter into such chemical com- 

 binations as would make them parts of solid bodies. More 

 and moie of the surface of the forming earth would thus 

 become solid, though doubtless there was very little perma- 



