5o6 



SCIENTIFIC NEWS. 



[June I, iS 



watched them they " rose with a motion almost per- 

 ceptible to the eye, until in ten minutes the uppermost 

 were more than 200,000 miles above the solar surface." 

 It should be noted that this velocity of 10,000 miles per 

 minute was the mean velocity of the latter half of the 

 observed upward journey ; the initial or starting velocity 

 must have been far greater, as the visible flames consisted 

 of gaseous matter projected through a resisting medium. 



Further details would carry me beyond my limits, but 

 something should be added concerning the nature and 

 origin of the force which probably produces these stupen- 

 dous eruptions, from which the sun is never entirely free, 

 their magnitude varying from barely visible mounds of 

 flame to such as above described. 



The spectroscope demonstrates that the pervading 

 material of the mighty flash is flaming hydrogen, and we 

 know such flame is commonly due to the combination of 

 hydrogen with oxygen to form water. But the spectro- 

 scope is equivocal concerning oxygen in the sun, and much 

 discussion has arisen on this point. My reply to all 

 this is very simple, viz., that if we turn our spectroscope 

 to a terrestrial hydrogen flame, to hydrogen in the act of 

 combining with oxygen, the spectrum does not display the 

 oxygen there any more decidedly than in the hydrogen 

 flames of the solar prominences. Ergo, it is the spectro- 

 scope, not the oxygen that is at fault. 



Nearly twenty years have elapsed since I ventured to 

 affirm " that in the present state of our knowledge the 

 spectroscope does not afford any reliable information 

 respecting the existence or non-existence of metalloids in 

 the sun — they may all be there though the spectroscope 

 should not detect one of the them "("The Fuel of the 

 Sun," page 141 ) — and stated my reasons for this conclusion 

 I still maintain the same in spite of all the progress made 

 since that time. 



But I am already at or near the end of my second 

 column, and therefore must ask the editor to allow me 

 to take up this subject of the cause of the solar outbursts 

 next week. It is not only a big one but is very interest- 

 ing, and by no means limited to what is going on in the 

 central luminary of our own astronomical family. 



THE ARTESIAN WELL OF THE PLACE 

 HEBERT, PARIS. 



A RTESIAN wells are doubtless likely to play an im- 

 ■^ portant part in the economy of the future. Not 

 merely are they destined to furnish supplies of water 

 where there is otherwise a deficiency, but it is at least 

 possible that they may become sources of heat. In 

 many places the temperature of the water rising from 

 great depths is sufficiently high to serve for heating pur- 

 poses of various kinds. 



The well in the Place Hebert, which has been in pro- 

 gress for a long time, has now reached, at a depth of 

 719 metres, the subterranean water which it is intended 

 to bring to the surface. Geologists and engineers find here 

 the results of a new inquiry into the constitution of 

 strata, into the movements and the character of Ihe deep- 

 lying waters, as well as into the powerful methods of 

 boring, which are ever being improved. 



The borings in the Place Hebert at La Chapelle have 

 been undertaken and conducted by M. Lippmann, of 

 Paris. The bulk of the work is accomplished ; only the 

 final casing-in remains to be finished, and in the mean- 

 ti me the rising water is turned into an adjoining sewer 



The diameter of the well is rather more than a metre, and 

 if we remember that other borings in France and else- 

 where do not exceed one-fifth of a metre, we see how 

 considerable is the advance now effected. 



The soil of Paris, as of all places suitable for useful 

 artesian operations, is superimposed upon several sub- 

 terranean beds of water, alternating with sedimentary 

 strata, permeable or not, The ascensive force of these 

 different supplies depends on the altitude of their origin. 



The sheet of water reached by the well in question 

 exists between the depths of 704 and 720 metres, lying 

 in a watery sand, and its origin is probably in Cham- 

 pagne. Its purity is great ; it does not mark more than 

 8° on the hydrotimetric scale, whereas the administrative 

 regulations permit the use of a water supply which does 

 not exceed 15° of this scale. The great natural filter 

 of sand upon which the well opens insures a regular 

 purification of the water. 



The temperature of water on the surface being 

 53° Fahr., that of the well is about 86° Fahr., in virtue 

 of the well-known law which gives approximately an 

 increase of 11° Fahr. for every 100 feet of depth. 



When we find in an artesian well several sheets of 

 water, the deepest is generally the most powerful, and it 

 is advisable to secure it by stopping off the others. Expe- 

 rience shows that the power of absorption of a water- 

 sheet is at least equal to the power of its yield. If the 

 upper sheets of a well are left in communication with 

 the lowest sheet, this last only discharges what the others 

 have left it. It is therefore necessary to mask by a 

 water-tight casing all the water-beds traversed before 

 reaching the one which it is intended to use. A well 

 executed at the Hospice of Tours has proved that such is 

 the case. The borings traversed three shallower beds, 

 which were completely shut off; the fourth, struck at a 

 depth of 170 metres, gave a flow above ground of more 

 than 875 gallons per [minute; whilst from another well, 

 previously sunk at the same establishment, of the same 

 diameter, at the same level, and to exactly the same 

 depth, which had traversed the same beds of water, 

 but which were left in communication with each other, 

 the yield was only one-fourth the quantity. Hence the 

 best means are studied for blocking off the waters met 

 with in the tertiary formations and on the surface of the 

 cretaceous strata. 



The methods of boring and casing used in practice can 

 be here but briefly touched upon. They are known as 

 rope-boring or Chinese-boring, hollow-tool boring, and black 

 diamond- boring, or rather perforation by means of black 

 diamonds. These processes are chiefly methods of ex- 

 ploration suitable only for small diameters. If large 

 diameters are reached, such as 20, 24, or 28 inches, the 

 rigid boring system is used. The rods are made of wood 

 or iron, and the perforation is effected by a tool which 

 breaks up the rocks by percussion. The boring tools 

 employed at the Place Hebert are of this kind, but with 

 a free Jail. The rod of the borer is counterpoised, and 

 the percussion upon the bottom to be perforated is effected 

 by letting fall only the lower part of the borer, which is 

 made very heavy. In this manner the power needed for 

 pounding with the tool at the depth of 800 to 1,000 metres 

 is not greater than at 100 metres, and the maximum 

 effort is needed only when it is required to bring up the 

 tool which was working at the bottom on account of some 

 accident. 



The tools of the borer, in searching for Artesian waters, 

 constitute quite an arsenal. Our illustration, borrowed 



