Oct. 21, 1875] 



NATURE 



545 



of the people lead them still to the earth, as the most fitting 

 resting-place into which, when lifeless, they should be drawn. 



Thus the cemetery holds its place in our city, but in a form 

 much modi^.ed from the ordinary cemetery. The burial-ground 

 is artificially made of a fine carboniferous earth. Vegetation of 

 rapid growth is cultivated over it. The dead are placed in the 

 earth from the bier, either in basket-work or simply in the 

 shroud ; and the monumental slab, instead of being set over 

 or at the head or foot of a raised grave, is placed in a spacious 

 covered hall or temple, and records simply the fact that the per- 

 son commemorated was recommitted to earth in those grounds. 

 In a few months, indeed, no monument would indicate the 

 remains of any dead. In that rapidly-resolving soil the trans- 

 formation of dust into dust is too perfect to leave a trace of 

 residuum. The natural circle of transmutation is harmlessly 

 completed, and the economy of nature conserved. 



Results. 



Omitting, necessarily, many minor but yet important details, 

 I close the description of the imaginary health city. I have yet 

 to indicate what are the results that might be fairly predicted 

 in respect to the disease and mortality presented under the con- 

 ditions specified. 



Two kinds of observation guide me in this essay : one derived 

 from statistical and sanitary work, the other from experience, 

 extended now over thirty years, of disease, its phenomena, its 

 origins, its causes, its terminations. 



I infer, then, that in our model city certain forms of disease 

 would find no possible home, or, at the worst, a home so transient 

 as not to affect the mortality in any serious degree. The infan- 

 tile diseases, infantile and remittent fevers, convulsions, diarrhcea, 

 . croup, marasmus, dysentery, would, I calculate, be almost 

 unknown. Typhus and typhoid fevers and cholera could not, I 

 believe, exist in the city except temporarily and by pure acci- 

 dent ; small-pox would be kept under entire control ; puerperal 

 fever and hospital fever would probably cease altogether ; rheu- 

 matic fever, induced by residence in damp houses, and the heart 

 disease subsequent upon it, would be removed ; death from 

 privation and from puerpera and scurvy would certainly cease ; 

 delirium tremens, liver disease, alcoholic phthisis, alcoholic 

 degeneration of kidney, and all the varied forms of paralysis, 

 insanity, and other affections due to alcohol, would be ccmpletely 

 effaced. The parasitic diseases arising from the introduction into 

 the body, through food, of the larva- of the entozoa, would 

 cease, and that large class of deaths from pulmonary consump- 

 tion, induced in less-favoured cities by exposure to impure air 

 and badly-ventilated rooms, would, I believe, be reduced so as 

 to bring down the mortality of this signally fatal malady one- 

 third at least. 



Some diseases, pre-eminently those which arise from uncon- 

 trollable causes, from sudden fluctuations of temperature, electri- 

 cal storms, and similar great variations of nature, would remain 

 as active as ever ; and pneumonia, bronchitis, congestion of the 

 lungs, and summer cholera would still hold their sway. Cancer, 

 also, and allied constitutional diseases of strong hereditary cha- 

 racter would yet, as far ?s we can see, prevail. I fear, more- 

 over, it must be admitted that two or three of the epidemic 

 diseases, notably scarlet fever, measles, and whooping-cough, 

 would assert themselves, and, though limited in their diffusion 

 by the sanitary provisions for arresting their progress, fvould 

 claim a considerable number of victims. 



With these facts clearly in view, I must be careful not to claim 

 for my model city more than it deserves ; but calculating the 

 mortality which would be saved, and comparing the result with 

 the mortality which now prevails in the most favoured of our 

 large English towns, I conclude that an average mortality of 

 eight per thousand would be the maximum in the first generation 

 living under this salutary rcLiitiie. That in a succeeding genera- 

 tion Mr. Chadwick's estimate of a jiossible mortality of five per 

 thousand would be realised, I have no reasonable doubt, since 

 the almost unrecognised though potent influence of heredity in 

 disease would immediately lessen in intensity, and the healthier 

 parents would bring forth the healthier offspring. 



As my voice ceases to dwell on this theme of a yet unknown 

 city of health, do not, I pray you, wake as from a mere dream. 

 The details of the city exist. They have been worked out by 

 those pioneers of sanitary science, so many of whom surround 

 me to-day, and specially by him whose hopeful thought has 

 suggested my design. I am, therefore, but as a draughtsman, 

 who, knowing somewhat your desires and aspirations, have 

 drawn a plan, which you in your wisdom can modify, improve, 



perfect. In this I know we are of one mind, that though the 

 ideal we all of us hold be never reached during our lives, we 

 shall continue to work successfully for its realisation. Utopia 

 itself is but another word for time ; and some day the masses, 

 who now heed us not, or smile incredulously at our proceedings, 

 will awake to our conceptions. Then our knowledge, like light 

 rapidly conveyed from one torch to another, will bury us in its 

 brightness. 



By swift degrees the love of Nature works 



And warms the bosom, till at last, sublim'd 



'J'o rapture and enthusiastic heat. 



We ftel the present Deity, and taste 



The joy of God to see a happy world ! 



THE INTERNAL HEAT OF THE EARTH 



pROF. MOIIR, of Bonn, has contributed to the A^eues Jahr- 

 ■*• buchfiir Mineralo^ie, &c. (1875, Heft 4), a very important 

 paper on the causes of the internal heat of the earth. After 

 indicating some of the objections which may be urged against 

 the Plutonistic theory of the origin of the earth's internal heat, 

 he discusses the data obtained by the thermometric investigation 

 of a boring about 4,000 feet deep, through pure rock salt," at 

 Speremberg, near Berlin. 



The proposition from which he 'starts is as follows : — If the 

 interior of the earth is still fused, then with every increase in depth, 

 as we approach this furnace, a less space must be necessary to 

 produce the same increase of heat. The heat passes outwards 

 by conduction from a smaller into a constantly enlarging sphere, 

 and supposing the conductivity of the materials to be uniform, 

 the temperature of the outer coats of the sphere must gradually 

 diminish in proportion as their volume increases ; or, in other 

 words, the increase of heat per 100 feet must become greater and 

 greater in proportion as we descend. 



Now the results of the thermometric investigation of the 



Speremberg boring give the following numbers : — 



,, J I r Increase per 



for a depth of 100 feet 



700 feet 15654° R — 



900 ,, i7'849 „ i'097 



I roc „ 19-943 .. I '047 



1300 ,, 21-039 ,, 0-997 



1500 ,, 23830 ,, o 946 



1700 ,, 25-623 ,, 0-896 



1900 ,, 27-315 ,, 0-846 



2100 ,, 28-906 ,, 0-795 



3390 .. 36 756 ,, 0-608 



The third column is a diminishing arithmetical series of the first 

 order, showing equal differences of 0050° or tjV 1^- fo"^ every 

 lOO feet By applying this principle to the gaps left above 700 

 feet and between 2,100 and 3,390 feet. Prof. Mohr gets the fol- 

 lowing table of increase of heat for the whole depth :— 



Depth. 



100 to 200 feet 



200 „ 3C0 „ 



300 „ 400 „ 



400 „ 500 „ 



500 „ 600 „ 



600 „ 700 „ 



700 „ 900 „ 



900 „ I ICO „ 



1 100 „ 1300 „ 



1300 „ I 500 „ 



1500 „ 17CO „ 



1700 „ 1900 „ 



1900 „ 2100 ,. 



2100 „ 2300 „ 



2300 „ 2500 „ 



2500 „ 2700 „ 



2700 „ 2900 „ 



2900 „ 3 ICO „ 



3100 „ 3300 „ 



3300 „ 3390 „ 



Increase per 

 100 feet ill depth. 



... 1-35 " K. 



... 130 „ 



... 125 „ 



... 120 ,, 



... I-I5 M 



... i-io ,, 



... 1-097 „ 



... 1-047 M 



... 0-997 M 



... 0-946 ,, 



... 0-896 „ 



... 0846 ,, 



.•• 0-795 „ 



• •■ 0745 „ 



• •• 0-695 .. 

 ... 0-645 .. 

 ... 0-595 „ 

 ... 0-545 „ 

 ... 0-495 ,. 



... 0-445 M 



and from this series he concludes that at a depth of 5,170 feet 

 the increase will be ////, because, as he says, " the end of the 

 increase will come when the last increase of 0-445'' R. is ab- 

 sorbed by the deduction of 0-05° R., therefore after —^ or 8-9 

 strata of 200 feet, and therefore 1,780 feet deeper than 3,390 



