Sept. 5, 1889] 



NATURE 



437 



factures, and to the phenomena of every-day life. The 

 subject of ventilation, for example, is very fully discus-ed 

 and illustrated by experiments. There is also a beautiful 

 experiment illustrating the intermittent action of geysers 

 (p. 195). Perhaps the most important application of the 

 laws of heat, however, is the steam-engine ; and most 

 of the various forms, including locomotive and marine 

 engines, are described. Even the gas-engine is briefly 

 referred to. 



There are no less than 138 excellent diagrams dis- 

 tributed throughout the- text, most of which have been 

 specially prepared for the book. 



British Rainfall, 1888. By G. J. Symons, F.R.S. 

 (London : E. Stanford, 1889.) 



This work is a general summary and epitome of a year's 

 work, and contains a Report upon the progress of rainfall 

 investigations. 



The volume is divided into three parts : the first deals 

 with the measurement of snow, experimental gauges, the 

 Camden Square evaporation experiments, and concludes 

 with a list of the staff of observers, showing that the staff 

 is still on the increase, although very slowly, the chief 

 increase being in England. 



The second part treats of the rainfall and meteorology 

 for the year, as reported from the various observing sta- 

 tions. One of the heaviest short-period rains recorded 

 is that which fell on March 24 at Chepstow, Shirenewton 

 Hall ; it lasted two minutes, and in that time the ground 

 was covered 2 inches deep with snow, the flakes being 

 3| inches in diameter, and only \ inch thick, 6 inches 

 of this snow yielding i inch of water, so that, if the 

 snow had lasted one hour, it would have reached an 

 average depth of 5 feet. 1 



Maps and tables indicate the monthly rainfall for the 

 year, the greatest fall being at " The Stye," in Cumber- 

 land (i75'40 inches), the least at Skegness, in Lincoln- 

 shire (i7'5o inches). 



Lastly, Part III. consists of general tables of the total 

 rainfall at the 2500 places of observation. 



Putting together all the above facts, we find that during 

 the year there was much dry weather, although few 

 droughts ; there were hours and days of excessive rain, 

 months with amounts of rain almost without precedent. 

 Yet, on the whole, we get a result not at all remarkable, 

 but decidedly below the average. 



Rainfall observers will find in this book a collection 

 of most interesting tables, maps, and articles upon the 

 various branches of the work ; and as the new decade 

 begins with January i next year, we hope that the staff 

 of observers will number many of our readers among 

 them. 



Ancient Art of the Province of Chiriqtii. By W. H. 



Holmes. (Washington: Government Printing Office. 



1888.) ' 



This is an extract from the sixth Annual Report of the 

 U.S. Bureau of Ethnology, and will be read with interest 

 by all students of American antiquities. Chiriqui occupies 

 a part of the Isthmus of Panama, and at the present time 

 is inhabited chiefly by Indians and natives of mixed blood. 

 Many ancient cemeteries have been discovered along the 

 Pacific slope of the district, and explorers have found in 

 them a great quantity of more or less valuable objects of 

 art. These objects Mr. Holmes has classified, and in the 

 present monograph he carefully describes the character- 

 istics of typical specimens. He first deals with the graves 

 and their human remains, then passes on to consider, in 

 order, objects in stone, objects in metal, and objects in 

 clay. His descriptions are concise and lucid, and their 

 value is greatly increased by a large number of excellent 

 illustrations. Mr. Holmes is careful to point out that 

 there is no valid reason for assigning a very high antiquity 

 to the works of art found in Chiriqui. The tribes by whom 



the graves were made may, he thinks, have been in 

 possession of the country, or parts of it, at the time of the 

 conquest. Their pottery appears to indicate that they 

 were more closely related with the ancient Costa Rican 

 peoples than with those of continental South America ; but 

 in their burial customs, in the lack of enduring houses and 

 temples, and in their use of gold, they were, as Mr. 

 Holmes shows, like the ancient peoples of middle and 

 southern New Granada. 



An Elementary Treatise on Dynamics. By Benjamin 

 Williamson, F.R.S., and Francis A. Tarleton, LL.D. 

 Second Edition. (London : Longmans, Green, and 

 Co, 1889.) 



This work has been thoroughly revised, and a con- 

 siderable alteration has been made in the order of its 

 arrangement. The first half of the book treats of the 

 dynamics of a particle, while the latter part deals with 

 kinematics and kinetics of rigid bodies. 



Many portions of the subject have been developed, and 

 in some cases rewritten, especially that on generalized 

 co-ordinates in connection with Legrange's and Hamil- 

 ton's methods ; the general theory of oscillations is 

 exhibited in a new form. 



The work has been arranged from the most elementary 

 conceptions, so that anyone acquainted with the con- 

 ditions of equilibrium, and with the notation of the cal- 

 culus, may commence the treatise without studying any 

 other book on the subject. 



LETTERS TO THE EDITOR. 



[ The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications. ^ 



On some Effects of Lightning. 



During the thunderstorms of the 6th and 7th of June last, 

 some twenty trees and buildings were struck within a 5-mile radius 

 from Cranleigh. I have examined most of the trees struck, and 

 have found a remarkable similarity in the effects, which are of 

 two kinds : the first, by far the most common effect, is simply 

 a score out of the bark up the trunk of the tree, out along one 

 limb, and then by perhaps two or three smaller branches to the 

 outer twigs ; the other effect is the shattering of the tree, which 

 occurs, as Mr. Griffith remarks in Nature of August 15 (p. 366), 

 when the lightning course leaves the outer surface of the tree and 

 enters between the bark and the wood at the junction of some 

 main branch with either the stem or with some other branch, 

 when the shattering would probably occur from some obstruction 

 at the junction, or from there being water in a cavity or in a 

 collection of dead leaves in the fork. 



I imagine that in general the course of the electricity is 

 outside of the bark, following one or more lines of moisture or 

 running water down the tree ; when this conductor becomes 

 insufficient a discharge takes place, and the stream of water is 

 converted into steam so violently as to destroy the bark instantly 

 along the line of strain. If the sap within be also converted into 

 steam by communication through a knot-hole or by a flaw, the 

 bark is blown off altogether. 



If the tension be very great indeed, and especially if the air 

 round the tree be dry, the sap may be violently exploded, and 

 the trunk splintered and shattered as if by dynamite. 



Most of the trees in this neighbourhood were struck while it 

 was raining ; but one tree, a Scotch fir, occupying a prominent 

 position on the side of a hill, was struck before any rain fell. 

 This tree divided out into two arms nearly in line with the stem ; 

 one arm was thrown to the ground, the other remained up for a 

 few hours, and was then blown down by the wind, falling in the 

 opposite direction to the first arm. At the junction there was a 

 great deal of turpentine which was thoroughly blackened. The 

 trunk below the arms was shivered, and tlie bark thrown out to a 



