May 24, 1906] 



NA TURE 



69 



Koiomahana. Lake Rolomahana is a sheet of dirty, 

 muddy green water, some three and a half miles long by 

 le!.s than two miles in the opposite direction, and with a 

 maximum depth of 427 feel. In continuation along the 

 same line, beyond Lake Rotomahana, are the deep holes 

 firjning the Black, Fourth, Waimangu, Inferno, Echo 

 l.akr', and Southern craters. Hot water and steam issue 

 in largrr or smaller quantities from these craters, the 

 water linding its way to Lake Rotomahana. 



The most remarkable feature of the region during the 

 l.i^t few years has been the great geyser of Waimangu. 

 This geyser was discovered in January, 1900, and is believed 

 III have become active only a short time before that date. 

 While playing, outbursts occurred nearly every day, and 

 Miinetimes more frequently. Mud, sand, and immense 

 linulders were shot up in huge columns of dirty black 

 water. .At some hundreds of feet above the water the 

 11 lumn broke, showering boulders, mud, and sand back 

 into the pool, and even high up on the walls surround- 

 ing it. 



In Julv. 1004, the gnat geyser suddenly ceased, and 

 ri'iiiaiiiptl dormant for si-ven weeks and live davs ; then it 



Fi>,. I. -Highest knoiMi eruption of Waiiiir 



again burst into action, and until Nuveiiiber i foUow-ing 

 outbursts occurred almost daily. Then it stopped, and sini e 

 then there has been no further explosive activity. We 

 reproduce a photograph of the highest known eruption of 

 Waimangu, from the illustrations accompanying Mr. Bell's 

 paper. It is estimated that this " shot " ascended 1500 feet 

 above the water, and carried a voluire of 800 tons. 



HYDROLOGY IN THE UNITED STATES. 

 n^IlE papers relating to the hydrological work in the 

 United States which are issued by the department of 

 the Geological survey have from time to time been noticed 

 in Nati RE. We have now to acknowledge twenty-six of 

 the papers last issued. The greater part of these relate to 

 the progress of stream measurements in the different 

 States, and to other matters which are of local interest. 

 There are, however, some of the papers that deserve the 

 attention of those engaged in works of water supply. 



On a previous occasion, in Nau're of December 21, 

 1905. we gave a short account of the investigations that 



are being made as to the movement of underground water. 

 A further paper on this subject has now been issued as 

 the result of investigations made by Prof. Slichter, No. 

 140, on field measurements. 



This paper presents an amplified exposition of the 

 method of measuring underground water as described in 

 his former paper of 1902. It contains descriptions of the 

 apparatus used for the laboratory study of wells controlling 

 horizontal and vertical movements, and the result of these 

 studies confirms the conclusions described in the former 

 paper as to the possibility of measuring the flow of sub- 

 surface water with trustworthy accuracy. Some improve- 

 ments that have been made in the apparatus as the result 

 of experience are described. 



The author shows that the flow of water in a given 

 direction through a column of .sand is proportional to the 

 difference in pressure at the ends of the column, and 

 inversely proportional to the length of the column, and is 

 also dependent upon a factor which he terms the trans- 

 mission constant of the sand. 



Experiment shows that the resistance to the flow of 

 w.itiT through -.and i< vi ry great, the water having to 

 pass through pores, usually 

 capillary in character, and 

 the diameter of which varies 

 froin one-fourth to one-seventh 

 of the diameter of the sand 

 particles. When the sand is 

 not of uniform size, and is 

 mixed with grains slightly 

 larger, the effect is to increase 

 the capacity of the sand to 

 transmit the water. Where 

 particles seven to ten times 

 the diameter of the original 

 sand grains are added, each 

 of these tends to block the 

 course of the water. For 

 example, a boulder placed in 

 a mass of fine sand checks 

 the passage of the water, and 

 the rate of flow decreases in 

 proportion to the number of 

 such boulders until the amount 

 of the large particles is equal 

 to about 30 per cent, of the 

 total inass. After this the 

 flow increases until the mass 

 of fine particles becomes 

 ii<gligible, and the capacity to 

 ransmit approaches that of 

 ihe mass of large particles 

 I lone. 



These facts are shown to 

 have an important bearing 

 upon the capacity of gravels 

 to furnish water to wells, or 

 igu. to transmit it in the under- 



flow to rivers. 

 Tables are given showing the transmission constant for 

 .sands and gravels of different sizes and different degrees 

 of porosity. 



It is also shown that the rate of flow is affected by 

 temnerature, a change froin freezing point to 75° nearly 

 doubling the power of the soil to transmit water. This 

 paper contains a great deal of information as to the dis- 

 charge from wells used for irrigation or other purposes. 



Paper No. 144, by Mr. Daniel D. Jackson, deals with 

 the normal distribution of chlorine in the natural waters 

 of New Vorlc and New England. The author shows that, 

 with the exception of local deposits, the normal chlorine in 

 natural waters is derived from the salt of the ocean, blown 

 over the land bv storms, and that it diminishes in amount 

 as the distance from the ocean increases. This decrease is 

 so definite that equal amounts of chlorine are found along 

 lines generallv parallel to the sea coast, thus affording a 

 basis for the establishment of isochlors. Charts and tables 

 are given showing the proportion of chlorine at different 

 distances from tliV coast. The sainples were taken from 

 ponds or open water basins as far removed from human 



NO. 1908, VOL. 74] 



