NOTES AND QTJEIilES. 



153 



oscillations in this column of water, during which the steam finds opportunity to escape, 

 and carries up with it a great part of the water. Another class of writers have adopted 

 a theory put forward by Bunsen, in which the Geyser tube alone, without a subterranean 

 cavern, is supposed to contain water, heat being applied to the tube itself, and the relief 

 of pressure which results from the elevation of the upper portion of the water playing an 

 important part in the operation. In this case, however, as in the former, the notion of 

 steam being suddenly generated is preserved, heated rocks being supposed to furnish the 

 necessary supply of local heat. 



" Now, Mr. Williams's theory most amply and beautifully accounts for all the pheno- 

 mena of these Geysers, without assuming the existence either of intense local heat or of 

 sudden evolutions of heat. Simply assuming the existence of a subterranean heat of 

 some kind — and all now admit the existence of that — also the presence of water in and 

 below the tube, and, in his view, the generation and accumulation of steam must take 

 place. As the quantity of this steam goes on increasing, the moment will arrive when 

 the saturation of the water will have taken place, and after that a more or less violent 

 discharge of steam must follow. It seems reasonable to suppose that the Geyser tube is 

 not an isolated reservoir, and that it opens into wells or springs below of greater or less 

 extent ; and in this way the enormous amount of the discharges that issue from these 

 Geysers may be accounted for, whereas the tube alone seems of wholly insufficient capa- 

 city to supply them. 



" I would now ask you to observe the apparatus which we have here, and which Mr. 

 Williams himself constructed. It consists simply of a t ube opening into a vessel of water 

 below, and a basin above, the tube and lower vessel being tilled with water which rises 

 up and partly fills the basin. Heat is now applied below ; steam is, as we think, accu- 

 mulating in the water ; now you hear explosive sounds and observe commotion in the 

 fluid; and now a violent and copious discharge of steam and water-bursts, Geyser-like, 

 from the basin. The action now subsides ; the water returns from the basin down the 

 tube to the reservoir below ; and presently all these phenomena will repeat themselves, 

 just as they do in nature. The Geyser, then, like the miniature working model before 

 us, consists of a large reservoir below, a single tube or orifice of exit, and a basin above, 

 which, receives a large portion of the ejected water, to be returned to the reservoir below. 

 This reservoir being necessarily full of water, the steam generated must remain and ac- 

 cumulate in it until the point of saturation has been reached, which will depend on the 

 height of the column of water in the vertical tube of exit, the temperature in the reser- 

 voir corresponding with that elevation. In the miniature, that temperature is found to 

 be 215° when the discharge takes place. In the Geyser, this must be considerably higher, 

 the tube of exit being there 47 feet. We thus see that the Geyser and its miniature 

 correspond in action and result." 



Shell-Mounds. — Dr. Collingwood, in the Proceedings of the Liverpool 

 Philosophical Society (1863), says, " My friend Mr. I. Byerley, of Sea- 

 combe, has met with remains on the shores of the Mersey, which appear 

 to resemble the deposits known as kitchen middens. He informs me ' that 

 strata of shells exist at Wallasey, and in the sand-hills along the shore, be- 

 tween Leasowe and Hoylake, which seem to resemble, on a small scale, 

 the collections noticed by Mr. Lubbock, under the name of 6 shell mounds ' 

 in Scotland, and of ' Kjokkenmoddings ' in Denmark. On going down the 

 hill, just before entering Wallasey village, there is a bank, which may be 

 twenty feet or more high, on the right-hand side ; two-thirds of its height 

 is composed of sandstone, above which is a covering of earth from four to 

 six feet in thickness ; between the latter and the sandstone, a stratum of 

 mussel-shells, about eight inches thick, may be seen. The shells are partly 

 whole and partly broken ; all, of course, are free from epidermis, but the 

 striated colouring is as distinct as in recent specimens of the species. 

 Having, however, lost much of their animal element, they are more friable ; 

 and on being placed in water for the purpose of cleansing them, the outer 

 layer of shell-structure readily separates from the nacreous interior. This 



YOL. VII. X 



