534 



NA TURE 



{April ^, 1889 



At the close of the Congress addresses were given to 

 the working classes of the town of Bolton. The Sanitary 

 Institute appears to fully recognize the desirability of 

 bringing home to the minds of all classes of the com- 

 munity the importance of healthy homes and temperate 

 living ; and the lesson it should aim at inculcating is that 

 if the public sanitary authorities can do much for the 

 working man, he can do for himself by his own efforts— 

 if he only knew how— very much more to improve his 

 own surroundings, and bring up his family in health 

 and comfort. 



The annual visits of the Institute, for the purpose of 

 holding Congresses, to the large towns of this country, 

 must rank as one of the most influential means of 

 popularizing sanitary science. The proceedings of the 

 Congress are watched with interest by persons whose 

 attention it is not easy otherwise to engage ; whilst the 

 exhibition of sanitary appliances brings under their 

 notice the latest improvements in domestic and muni- 

 cipal sanitation, and is an incentive to manufacturers to 

 turn out none but the most approved articles. 



It also appears that the Institute holds examina- 

 tions and grants certificates to local surveyors and 

 inspectors of nuisances to sanitary authorities. These 

 examinations should prove of the greatest use to the 

 public sanitary service, for the certificate is a guarantee 

 that the holder possesses sound knowledge on sanitary 

 subjects ; and there can in future be no reason why 

 Local Boards should appoint incompetent and ignorant 

 officials, when certificated candidates for office present 

 themselves. 



GLEANINGS IN SCIENCE. 

 Gleanings in Science. By Gerald Molloy, D.D., D.Sc. 

 (London : Macmillan and Co., 1888.) 



THIS is a pleasantly-written book, containing ten 

 popular lectures which have, from time to time 

 been delivered by the author to popular audiences. They 

 were, with one exception, delivered under the auspices of 

 the Royal Dublin Society. The lectures are not offered 

 as containing anything new, but simply as an attempt to 

 popularize some of the most important of modern 

 developments in physical science. 



The author has, in our opinion, been thoroughly suc- 

 cessful. In a short space he has been able to put before 

 his hearers and his readers, in a satisfactory and 

 thoroughly intelligible manner, a great variety of most 

 important scientific facts and principles. The subjects 

 of the lectures are well chosen. 



First, we have two lectures on " Latent Heat," in which 

 the fundamental discoveries of Black are explained and 

 the great results which have flowed from them are 

 recounted. Three lectures on electrical subjects follow. 

 Then we have two' lectures on " The Sun as a Store- 

 house of Energy." Two lectures on the Electric Light 

 enable the author to lay before his readers in a popular 

 but scientific manner the principles of dynamo-machines 

 and the modes of producing the light from the electric 

 current. The transformations of energy which take place 

 during production of the light are also explained. The 

 last lecture is on the Glaciers of the Alps. 



The illustrations, which take the place of the experi- 



ments of the original lectures, are for the most part 

 suggestive and satisfactory. The lecture on glaciers 

 contains three or four striking, if somewhat sensational, 

 woodcuts by Mr. Whymper, whose Alpine sketches are 

 well known. 



A book of the kind we have described is scarcely likely 

 to be absolutely free from blemishes, particularly of style ; 

 and there are two or three to which we would call the 

 attention of the author. One of them, at any rate, can 

 be easily amended in another edition. It is the habit of 

 saying "indefinitely small" when he means either 

 infinitely small or extremely small. This use of the 

 word indefinite he shares with some, sometimes inde- 

 finite, writers on certain branches of mathematics and 

 dynamics. But indefinite does not in pure nor in common 

 language mean infinite; much less can "indefinitely 

 small" be put for " extremely small," as in speaking of 

 the length of the path of a molecule. There is nothing 

 indefinite about the path of a molecule any more than 

 about the path of a billiard ball. Again, there is nothing 

 " inconceivable " about the velocity of the radiant energy 

 of the sun (p. 191). It is measurable and well known. 

 The pruning down of some exaggerated language would 

 make the wonders of science all the more wonderful. 



A lover of Nature is apt to get into difficulties if he 

 invokes her aid too frequently in descriptions of the 

 physics of our universe. When we read of Nature deal- 

 ing out the sun's energy to man with the prodigality of a 

 spendthrift, we are apt to think of the much more prodigal 

 way in which the sun's energy is poured out all round. 

 The energy which comes in our direction is a very small 

 proportion of the whole. There are too many references 

 to personified Nature in these lectures. 



The parts which seem to us least satisfactory are the 

 early part of the lecture on storing of electrical energy, 

 and the classification of the forms of energy contained 

 in the next lecture. The enumeration of various forms 

 of energy available to man is very imperfect. For ex- 

 ample, energy of chemical separation is omitted from the 

 list, and yet dynamite, gunpowder, and the gas-engine, 

 are surely worthy of mention. Dynamite is manufactured 

 as electrical energy is ; but an engine worked, say, by 

 native petroleum, would be far more efficient than the 

 earth currents which Nature provides, but which, as our 

 author properly remarks, are more of a trouble than a 

 pleasure. In another place "bags of oxygen and hydro- 

 gen" are referred to as examples of stored-up heat. This 

 seems a little far-fetched, to say the least of it. Just 

 about the same place a rod of " chalk " is used to produce 

 the lime-light. 



Perhaps, however, it may seem somewhat ungracious 

 to prolong the list of minor corrections. The book is 

 most readable, and is deserving of praise throughout. 



OUR BOOK SHELF. 



The Gamekeeper's Manual; being an Epitome of the Game 



Laws of England and Scotland, and of the Gun 



Licences and Wild Birds Acts. By Alexander Porter, 



Chief Constable of Roxburghshire. Second Edition. 



Pp. 120. (Edinburgh : Douglas, 1889.) 



Assuming, and we are not in a position to affirm or 



deny the assumption, that the legal points laid down in 



this little book are sound, it will certainly fulfil its author's 



