July 14, 1898] 



NATURE 



263 



thus stimulated by dumping into the neck of the funnel large 

 pieces of turf. In the Yellowstone district, it has been found 

 that a small amount of soap or lye added to the geyser water 

 will frequently hasten eruption. This is explained by Hague 

 <"Soaping Geysers," Traits. A nier. Inst. Mm. Eng,\o\. xvii., 

 1889, p. 546) as due to the increased viscosity of the liquid. 

 "Viscosity must tend to the retention of steam within thebasin 

 and . . . explosive liberation must follow . . . Viscosity in 

 these hot springs must also tend to the formation of bubbles and 

 foam when the steam rises to the surface, and this in turn aids 

 to bring about the explosive action, followed by a relief of 

 pressure, and thus to hasten the final and more powerful dis- 

 play." Graham (American Journal of Science, January 1893,' 

 p. 54), as a result of experiments with an artificial geyser, agrees 

 that viscosity has much to do with the confinement of steam, 

 but questions the influence of bubbles and foam. 



Experiment ^. — The Effect of Soap. 



The apparatus was arranged to give regular eruptions as in 

 Experiment i, with the geyser-tube flush with the bottom of 

 the basin and the water maintained about an inch deep in the 

 basin without overflow. A small quantity of fine shavings of 

 Ivory soap was thrown into the basin : these gradually dissolved 

 and the milky solution was, after several eruptions, sucked into 

 the flask below. The occasional steam-bubbles, which, in pure 

 water, rise rapidly through the geyser tube and escape at the 

 surface during the intervals between eruptions, were less num- 

 erous, very small, and slower in their upward movement through 

 the soapy solution ; after five or six eruptions it became evident 

 that the intervals were somewhat shorter (averaging i min. 20-30 

 seconds, instead of i min. 30-40 seconds), and the periods very 

 noticeably longer (40-45 seconds, instead of 20 seconds). The 

 ebullition in the flask was more violent than in the case of pure 

 water, and columns of fine bubbles accumulated in the geyser- 

 tube, only to be ejected with a violent sputter and give place to 

 a new accumulation. It was evident that these accumulated 

 myriads of tiny steam bubbles, confined within the tube and 

 adhering to the walls of the tube, formed a cushion opposing 

 considerable resistance to pressure from below. 



After the diffusion of the soapy solution had become general, 

 the reservoir (and consequently the geyser-column) was lowered 

 to the level a ; the intervals were at once shortened to an aver- 

 age of about one minute, in consequence of the rapid accumu- 

 lation at the surface of the column and within the tube of the 

 cushion of steam bubbles. So resistant is this cushion, that as 

 it grows by the addition of new bubbles rising from below, the 

 water column is actually depressed, down to the neck of the 

 flask ; here a point is reached where the frictional resistance of 

 the froth cushion and the hydrostatic pressure are balanced. 

 A further accumulation of steam forces up the column of foam, 

 release of pressure permits the water to burst into violent 

 ebullition, and an eruption takes place. From this it would 

 appear that in those geysers where the tube is small, the growth 

 of a cushion of steam soap bubbles may play a very important 

 part in accelerating the development of eruptive conditions. 



Summary. 

 (i) Geysers and boiling springs are subject to the laws of 

 hydrostatic pressure, in common with other springs. 



(2) In a geyser-spring, overflow once established may be 

 maintained by convection even against a reversed head ; this 

 leads to a critical point in the spring's mode of discharge. 



(3) In this condition, with a constant source of heat, very 

 slight changes in the local head are suflicient to induce a change 

 in the nature of a geyser-spring's mode of action. Such change 

 in the head may be caused by variation in rainfall, by building 

 up a sinter cone by forcing new outlets at lower levels, or by 

 clogging of old conduits. 



(4) Geyser basins afford drainage channels for meteoric 

 waters. The drainage takes place by either continuous over- 

 flow (hot springs) or spasmodic eruption (geysers). Both types, 

 as well as transitional forms, are represented in the Yellowstone 

 Park. 



(5) In general, those geysers which are irregular in their 

 eruptions have continuously overflowing vents ; and the most 

 regular geysers have confined waters, which overflow only during 

 eruption. This is explained by the fact that the overflowing 

 vents are under hydrostatic pressure, cooler water from lateral 

 <iucts is continually replacing that which flows off^, and the 

 ebullition necessary to produce eruption is thus prevented ; 

 eruption can only take place in the seasons of minimal inflow 



NO. 1498, VOL. 58] 



of cooler water, when the heat is in excess. Where the water 

 is confined, on the other hand, and the supply of heat constant, 

 cooler water rushes in only after each eruption, and a definite 

 interval is required to bring it to the boiling point at the base 

 of the column. Overflowing and confined springs should be 

 distinguished in any description or classification of geysers. 



(6) For the artificial stimulus of geyser eruption, an important 

 effect of the bubble-forming alkalies, in small tubes, is the initial 

 depression of the water-column by the growth of a confined 

 cushion of minute steam bubbles. The release of pressure 

 induced by the final ejection of the froth column causes 

 eruption. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Dr. Merkii,l E. Gates has resigned the presidency of 

 Amherst College. 



The following appointments are announced :— Dr. Charles 

 Harrington to be assistant professor of hygiene, and Dr. 

 Franz Pfafi" to be instructor in pharmacology and physiological 

 chemistry in Harvard University ; Mr. jl. A. Emerson to 

 be assistant professor of horticulture at the University of 

 Nebraska. 



Science announces the following gifts for educational and 

 scientific purposes : — 50,000 dollars, from a source kept secret, 

 to Amherst College, for an academic hall in honour of Presi- 

 dent Seelye ; 20,000 dollars from Mr. H. L. Higginson, 

 treasurer of the J. W. and Belinda Randall Charities Corpor- 

 ation of Monson, Mass., for the erection of a building, or as a 

 permanent fund in connection with the University of Virginia. 

 Science also states that two conditional gifts of 50,000 dollars, 

 offered by Dr. D. K. Pearsons, have been secured by the colleges 

 collecting the additional sums required. The endowment of 

 Beloit College is thus increased by 200,000 dollars, and that of 

 Mt. Holyoke College by 150,000 dollars. 



The Calcutta Gazette reports that representatives of La 

 Martiniere and Doveton Colleges have been appointed to con- 

 sider the advisability or otherwise of the amalgamation of the 

 two institutions. It appears that for many years these two col- 

 leges carried on with efficiency, and at a standard which com- 

 pared favourably with corresponding schools in England, a large 

 portion of the work of secondary education in Calcutta ; but in 

 recent years both La Martiniere and Doveton, from causes over 

 which they have had little control, have fallen behind in the 

 race for up-to-date education. Owing to the keen competition 

 of newly-opened hill schools, and the consequent loss of 

 scholars and fees, also owing to heavy reduction in interest on 

 the capital invested in Government securities, these colleges 

 have not been able to keep pace with the requirements of 

 modern education; while, on the other hand, they have been handi- 

 capped by heavy expenditure on the up-keep of extensive build- 

 ings and the payment of large sums in municipal rates and taxes. 

 To remedy this state of affairs, which every year becomes more 

 serious and pressing, the amalgamation of the two institutions has 

 been suggested, in the hope that the result would be a consider- 

 able decrease in expenditure and a consequent gain in discipline 

 and efficiency. It is fully recognised that there are difficulties 

 in the way of the realisation of this scheme, but the Lieutenant- 

 Governor sees no reason to believe them insurmountable. The 

 aims and objects of the two institutions are almost identical, 

 and it is hoped that petty differences of detail may not be 

 allowed to stand in the way of arriving at a common under- 

 standing as to some broad scheme of amalgamation on lines 

 which, by uniting the resources of the two colleges, will 

 enable them to provide that standard of European education 

 which it was the intention of their founders to give, but which 

 under existing conditions it is practically impossible that either 

 college alone can supply from its unaided resources. 



, scM^JFJ:c serjals. 



TitB Mathefnatical Gazette, issued under the auspices of the 

 Mathematical Association, continues to maintain its interesting 

 collection of notes and solutions to problems. The June number, 

 recently issued, contains, in addition to these notes, papers by 

 Mr. H. B. Billups on the. connection between the inscribed and 

 escri bed circles of a triangle, and by Mr. R. F. Muirhead on 

 relative motion. We should be glad to see more articles in the 

 Gazette dealing with questions of general principle, rather than 



