July 1st, 1887.] 



SCIENTIFIC NEWS. 



115 



Disinfection v. Deodorisation. — It has often been 

 pointed out in our columns, as elsewhere, that deodorisa- 

 tion is one thing and disinfection another. The destruction 

 of bad smells by no means involves the destruction of 

 " infective agencies," but the destruction of bad smells is 

 also an important work, and one which every disinfectant 

 intended for general use ought to accomplish. Carbolic 

 acid is defective in this respect for, although a good dis- 

 infectant, it does not deodorise, and simply adds its own 

 disagreeable smell to those which existed before. Chlorine, 

 metallic chlorides — such as the chlorides of zinc, mercury, 

 and lead — sulphurous acid, and the alkaline permanganates 

 are far more effectual in this respect, and each possesses in 

 a greater or less degree the power of disinfection. Whilst 

 the " saucer " treatment of sick-rooms with a little Condy's 

 fluid or chloride of lime may well be distrusted, the lauda- 

 tion of such means as the use of euchlorinc (a mixture of 

 chlorine and chlorine peroxide) and bromine as aerial disin- 

 fectants cannot be commended. Sulphurous acid is some- 

 times underrated. As gas it is just as unsuitable in the 

 presence of patients as bromine or euchlorine, but in dilute 

 solution it is very active. Complete disinfection of an 

 infected atmosphere in the presence of patients is impossible, 

 but partial disinfection is easy, and the complete disinfec- 

 tion of wearing apparel, bedding, etc., by the prolonged use 

 of weak solutions of metallic chlorides, sulphurous acid, and 

 the like, can be readily eftected without the slightest injury 

 to the fabrics. — Lancet. 



Price-giving Scales. — The American Analyst describes a 

 very ingenious computing scale, the invention of Mr. L. A. 

 Meneger, of Lansing, Kansas. The scale consists of a simple 

 balance-arm resting on a nickel point, supported by a standard 

 about eighteen inches high. There are two scales on the 

 balance-arm. One denotes the weight and the total cost of the 

 article weighed, the other the unit of price, which is designated 

 by a sliding weight. From this sliding weight is suspended the 

 scoop or slab to contain the article to be weighed. By this 

 scale the total cost of any article to be weighed is given. For 

 instance, if ']\ pounds of butter be placed on the scale and the 

 price be 135 cents a pound, the scale shows at once that the total 

 cost is l.oij dol. Or if a purchaser wishes 16 cents' worth of 

 tea, the price of which is 75 cents a pound, the weight would be 

 fixed, the sliding one at 75 cents, the other one at the 16 cents 

 mark on the computing scale. Then, when enough tea should 

 have been put into the scoop to cause the scale to balance, that 

 quantity would be the 16 cents' worth desired. 



Improvements in Tin Cans. — An ingenious improvement in 

 the manufacture of tin cans for preserving food is being intro- 

 duced, the plan consisting simply in so forming the lid that it is 

 merely pressed on and the can is hermetically sealed, so that no 

 internal pressure can remove the lid. Water boiled in a tin thus 

 closed has failed to force it off, although the steam pressure has 

 burst the can itself A penny piece, however, used as a lever by 

 being placed under a rim formed around the top of the cover, 

 with the shoulder of the can as a fulcrum, raises the lid with a 

 remarkably small expenditure of power. The principle involved 

 in the device is that of the wedge and lever. The neck of the 

 tin on which the lid fits is formed at a very slight angle from 

 the vertical, and the rim of the lid is made at a corresponding 

 angle, no solder being used to form the joint. By means of this 

 arrangement, therefore, the opening of cans is rendered a 

 remarkably clean, quick, and simple operation, contrasting 

 greatly in these respects with the inconvenient method of open- 

 ing now in vogue. 



Foreign Awards to English Exhibitors. — In these days 

 of keen foreign competition it is refreshing to hear of foreign 

 awards being made to English exhibitors. For this reason, and 

 because of the excellence of their work, we congratulate 

 Messrs. Hartley and Sugden, of Halifax, the well-known makers 

 of horticultural and other hot-water boilers. They have just 

 been awarded a Gold and Bronze Medal at the International 

 Horticultural Exhibition held at Dresden, and in addition, the 

 Russian Imperial Horticultural Society of Riga have voluntarily 

 awarded them a special Silver Medal for the superiority of their 

 horticultural boilers over all others exhibited. 



REVIEWS OF BOOKS. 



Chips from the Earili's Crust. By John Gibson. London : 

 T. Nelson and Sons. 1887. 

 The title of this book fairly well describes it. The " Chips " 

 are pleasing to look upon, and may well attract attention to the 

 mass from which they have been chiselled. Such papers not 

 rarely carry the reader on to deeper researches into subjects 

 which have for the first time been rendered interesting to him 

 by the skilful, yet light-handed treatment of the author, who, 

 indeed, can hardly desire for them a better fate. The article on 

 Oil Wells strikes us as decidedly good, and that on Amber and 

 Meerschaum treats practically and sensibly of substances which 

 have always had about them a fascination, born possibly of the 

 many old-world stories wherein they figure as something akin to 

 the magical. 



The Steam Engine. By George C. V. Holmes. London : 

 Longmans and Co. 1887. 



This is one of the " Text-books of Science " series, and is 

 framed on the lines usually followed by the compilers of works 

 of that collection. The author covers the ground necessary for 

 the consideration of the subject as completely as can be done in 

 the limits of space at his command. It will be evident, however, 

 that in a small work of a single volume there must be much left 

 unsaid when the steam-engine and boiler have to be considered 

 theoretically and practically. 



The scope of the book is set forth in the preface, wherein the 

 author lays down four chief points he keeps in view, as 

 follows : — 



" I. The modern science of thermodjmamics, which is the 

 foundation of all knowledge of the steam-engine considered 

 as an apparatus for converting heat into mechanical work. 



" 2. The effects exercised on the motion of quick-running 

 engines by the inertia of their reciprocating parts. 



" 3. The geometrical methods of fixing the dimensions and the 

 setting of slide valves. 



" 4. The investigation of the methods in use for diminishing 

 the losses of efficiency in expansive engines, due to the cooling 

 of the cylinders by the expanding steam ; the principles of 

 which methods are superheating, steam jacketing, and com- 

 pounding." 



In the consideration of these problems, the author travels over 

 a very wide range of subjects. There is the usual introductory 

 matter, describing the action of steam in the cylinder, the way 

 in which it is admitted and allowed to escape by the slide valve, 

 and other details of steam-engine mechanism. The fact of 

 heat being a form of energy, Boyle's law, the heat of steam, 

 and other matters of a like nature are explained ; after which 

 the theoretically perfect engine is considered. The mechanics 

 of the steam-engine leads up to a chapter on the indicator, 

 which is followed by others on fuel, its combustion, and the 

 generation of steam. This is, of course, the boiler division 

 of the book, and the various forms of boiler are illustrated 

 and described. There is a chapter on condensers, and another 

 on the principal causes of loss of efficiency : in fact, the book, 

 as we have said, takes a wide range. The author begins with 

 the most elementary aspect of the question and carries the reader 

 forward until he finds himself amongst the higher mathematics, 

 the calculus being often used, and there are many formula: by 

 no means simple in their construction. The work, however, is 

 free from errors of a radical nature — at least, we have not been 

 able to detect any lapses from recognised and accepted 

 opinions. 



The Journal of Microscopy and Natural Science : Journal of the 



Postal Microscopical Society. Published quarterly. Vol. vi. 



part 22. Edited by Alfred Allen. London : Bailliere, 



Tindall, and Cox ; Bath : i, Cambridge Place. 



The Postal Microscopical Society is very well organised for 



promoting microscopical research, and for gradually developing 



the amateur into the observer and the investigator. Among the 



most important matter in this number is a very able paper by 



Mrs. Bodington on the "Evolution of the Eye." This lady 



points out one of the blundering flippancies of a late prominent 



naturalist of the Sensational School, who denies that the mole 



is blind, overlooking all the time the fact that its eyeballs have 



no optic nerve. " The External Anatomy of the Dor Beetle," by 



Mr. R. Gillo, is a clear popular account of a despised but most 



