October 9, 1890] 



NATURE 



583 



the mountain." Even in these latter measurements we have 

 results in which the extreme -variation is about 2000 feet, and 

 this distance compared with 4 miles (about the height of the 

 mountain) is a large quantity, and shows that a still more 

 accurate determination must be made before its height is placed 

 beyond doubt. 



From the results of the measurements of the heights of these 

 four mountains, the existing evidence seems to point to the 

 "Star Mountain" of Mexico, the peak of Orizaba, with its 

 18,200 feet, as the culminating point of the North American 

 continent. 



A NEW ELECTRIC LIGHT OTTO GAS- 

 ENGINE. 

 "PLECTRIC lighting is becoming so universal in all parts 

 ■"-^ at the present day, that we give an illustration of the 

 latest form of gas-engine made by Crossley and Brothers, 



Manchester. This engine, called the "High Speed Electric 

 Light Otto Gas-Engine," runs at 250 revolutions, and is de- 

 signed throughout to run at this exceptional speed. It is fitted 

 with most of the latest improvements, such as Crossley's tube 

 ignition, patent timing valve, and a special electric light gover- 

 nor, which makes it a very steady running engine for this kind of 



work. The makers claim that "electric light lamps can be driven 

 direct from the dynamo without fitting the dynamo with a fly- 

 wheel or disc, as has hitherto been done when a small gas or 



steam-engine has been used ; and that the light will be as 

 absolutely steady as is possible with any form of motive 



power. 



SCIENTIFIC SERIALS. 



The American Meteorological Jotirnal for September con- 

 tains an article, by Prof. H. A. Hazen, on Espy's experiments 

 on storm generation and the liberation of latent heat on cloud- 

 formation ; these were made about 50 years ago, and Prof. 

 Hazen states that they have never been checked, but have been 

 accepted without question by meteorologists. His own experi- 

 ments have led to different results, and he finds that deposition 

 from moist air does not set free latent heat. — E. B. Garriott 

 contributes an article on the origin of storms ; he attributes 

 their development to an excess of heat from the earth's surface 

 by radiation, and their progressive movement to the precipita- 

 tion of aqueous vapour at a considerable elevation, while the 

 direction in which they move is regulated by the disposition of 

 cold dry air found in areas of high pressure. For a verification 

 of these facts, he points to the storms of the North American 

 continent, a large majority of which originate over the great 

 plateau region in the lee of the Pacific coast ranges of moun- 

 tains, and advance towards the regions of greatest moisture 

 which embrace the Great Lakes, the Gulf of Mexico, and the 

 valleys of the principal rivers. — M. Faye has a supplementary 

 article on trombes and tornadoes, for the purpose of introducing 

 the figures illustrating his previous papers in the /ounial. — Mr. 

 M. W. Harrington contributes an instructive paper on forests 

 and soil temperatures. He has taken various sets of observa- 

 tions published in Germany and elsewhere, amounting altogether 

 to 150 years, and has discussed them by harmonic analysis for 

 various periods, with the view of finding the distribution of 

 temperatures in the soil within and out of the forest, at any 



NO. 1093, VOL. 42] 



depth, and at any time. The greatest difference between the 

 forest soil and that of the open fields is at the surface, the mean 

 difference of forest below open field being about 3°, but below 

 the surface the differences between forest and open field do not 

 progress uniformly. There appears to be a gain of heat in the 

 upper soil of the woods which the open fields do not have. 



American yournal of Mathematics, vol. xiii., No. I (Balti- 

 more, October 1890). — The opening paper (pp. 1-52), entitled 

 " Ueber die zu der Curve \V + /*"" + ^^^ = o im projectiven 

 Sinne gehdrende mehrfache Ueberdeckung der Ebene," is by 

 Mellen Woodman Haskell, a name not familiar to us, but be- 

 longing evidently to a mathematician of power. The discussion 

 is exhaustive, and is fully illustrated with diagrams in the text, 

 and two large-paged tables containing shaded diagrams. The 

 reader who is familiar with Klein's "Ueber eine neue Art 

 Riemann'scher Flachen " will easily follow the author's work. 

 An index supplies the student with a ready key to the matters 

 handled. — Prof. Cayley (pp. 53-58), in a note on a soluble quintic 

 equation, discusses one of the equations given in Mr. Young's 

 paper, "Soluble Quintic Equations with Commensurable Co- 

 efficients" (vol. X. pp. 99-130). The example considered is 

 x^ -f 3Jr- -^ 2x - I = o, the solutions of which the author shows 

 admit of being put in much simpler form than those given by 

 Mr. Young. — Then there is an instalment of a course of lectures 

 delivered at the Johns Hopkins University during the months of 

 January and February 1889, by Oskar Bolza. Its title is " On 

 the Theory of Substitution-groups, and its Applications to Alge- 

 braic Equations." The paper is divided into two parts. The/rj/ 

 develops the fundamental propositions, and concludes with a 



