[20] The largest of the Norwegian lakes, the Mjosen, is 1550 feet deep, and its surface 385 feet above the sea-level. Its bottom is about 1000 feet lower than the sea outside, or 500 to 800 feet below the bottom of the Christiana Fjord. The fjords, generally speaking, are very much shallower near their mouths than further inland, as though their depth had been determined by the thickness of the glaciers flowing down them, and the consequent limits of flotation and deposition. [21] This has been recently overcome to a great extent by using glycerine instead of water. [22] Since the above was written I have made some experiments with a solution of shellac in borax (obtained by long boiling), and hereby claim the invention of its application to this purpose, in order to prevent anybody from patenting it. I shall not do so myself. [23] Written during the coal famine of 1872–73. [24] From 1870 to 1880 the amount has risen from 110,431,192 to 146,818,622 tons per annum, an average increase of 3,638,743 tons per annum. [25] At the present time (1882) we are receiving the excessive supplies consequent upon the opening of new pits that, under the stimulus of high prices, were in the course of sinking when the above was written. Hence the present low prices. Presently the annual increase of consumption will overtake this increased supply, and another “coal famine” like that then existing will follow. This is not far distant. [26] “The Coal Fields of Great Britain,” pp. 447, 448. [27] In a paper on the Comstock mines, read at the Pittsburg meeting of the American Institute of Mining Engineers in 1879, by Mr. John A. Church, the hot mine waters are described as reaching 158° Fahr. (so hot that men have been scalded to death by falling into them). The highest recorded _air temperature_ there is 128°. These are silver mines, and vigorously worked in spite of this temperature and great humidity. A much higher temperature is endurable in _dry air_. [28] The scientific pedant of the Middle Ages displayed his profundity by continually quoting Aristotle and other “ancients.” His modern successor does the like by decorating his pages with displays of algebraical formulæ. In order to secure the proper respect of _my_ readers I here repeat the equation that I enunciated many years ago, “_c_ = _s_/_p_” where _c_ stands for civilization, _s_ for the quantity of soap consumed per annum, and _p_ the population of a given community. [29] Geologists who may be interested in seeing the results of this experiment, will find on the Edgbaston Vestry Hall, in Enville Road, near the Five Ways, Birmingham, some columns, massive window pieces, doorways, and ornamental steps cast from the fused Rowley Rag and slowly cooled. [30] In each of my three visits to America 1 lost about thirty pounds in weight, which I recovered within a few months of my return to the “home country” (of English-speaking nations).—RICHARD A. PROCTOR.