Dec. 26, 1884.] 



KNO^VLEDGE ♦ 



529 



in the Calciihis of Variations, DilFerenlial Equations, itc, 

 (ike. ; comprising propositions, formul.-f, and methods of 

 analysis, with abridged demonstration. The mathematical 

 student will derive real assistance from this synopsis, which 

 is the outcome of an obviously enormous amount of honest 

 work. 



Evolution in History, Language, and Science. Four 

 addresses delivered at the commencement of the Twenty- 

 fifth Session (1884-85) of the Crystal Palace Company's 

 School of Art, Science, and Litei-ature. (London : Crystal 

 Palace Company. 1884.) — The addresses collected under 

 the above title were delivered by Dr. ZeifB, the Rev. W. 

 Hales, Mr. H. E. Maiden, and the Eev. R. Thornton, and 

 tleal respectively with the study of general history, the 

 scientific study of geography, hereditary tendencies as ex- 

 hibited in history, and vicissitudes of the English language. 

 Those who have the interests of education at heart, as con- 

 tradistinguished from the detestable system of cram now in 

 vogue, may profit by the perusal of these lectures. If they 

 afford anything like a faithful reflex of the system and 

 character of the instruction in the schools whence they 

 issue, then may the Crystal Palace Company congratulate 

 itself on worthily ministering to the educational wants of 

 the'country. 



Christmas Gleams. Edited by W. E. Hodgson. (Glas- 

 gow : David Bryce & Son. 1884.) — Poems, ghost stories 

 (satisfactorily cleared up), and other tale?, by such contri- 

 butors as Mr. W. H. JIallock, Mrs. Lynn Linton, Lord 

 liosslyn, &c., make up this Christmas number. 



Romance and Reality. By Francis Ne.vle. (London : 

 J. W. Palmer i Co.) — This is the biography of a man 

 who, beginning as a child by selling for sixpence a blue 

 Cape triangular postage-stamp, which he picked up in the 

 street in Hackney, has become one of the largest stamp- 

 dealers in the woild. 



The Coinpendioits Calculator. By Daniel O'Gormax, 

 corrected and extended by J. E. Young. 26th Edition. 

 Revised by C. Norris. (London : Crosby Lockwood i Co. 

 1885). — This is the twenty-sixth edition of that well- 

 known work, O'Gorman's " Intuitive Calculations," a fact 

 testifying, perhaps, as strongly to its value as any that 

 could be adduced. It would be difficult to exaggerate the 

 usefulness of a book like this to every one engaged in com- 

 merce, or manufacturing industry. Crammed full as it is 

 with rules and formula' for shortening and employing cal- 

 culations in money, weights, and measures of every sort 

 and description. Without selecting an example from 

 either of the divisions devoted to a special trade, we will 

 pick one out at random from what we may term the more 

 general part of the work. To multiply by any number of 

 jiines. Rule : Add as many ciphers to the right-hand of 

 the multiplicand as there are nines in the multiplier, and 

 from the result subtract the original multiplicand, the 

 remainder will be the product. Multiply 2368 by 999. 



2368000 



2368 



Product 2365632 



The whole work is full of similar " dodges " for shorten- 

 ing and simplifyiug calculation. 



Before I Began to Speak. By a Baby. (London : Fleet 

 Printing Works.) — The particularly precocious infant who 

 relates his prelocutory experiences in this little tract, gives 

 numerous hints as to the management of babies generally, 

 which may be studied with profit by all to whose charge 

 they are committed. 



We have also on our table. In the Watches of the Night, 

 Vol. 5 (Remington .fc Co.), Our Monthly (Rangoon), The 

 Tricyclist, and the Medical Press and Circidar. 



i¥li5rfllanra. 



A New Process of Photographic Printing. — The idea of coat- 

 ing paper with a gelatino-bromide of silver foUowed obviously 

 enough on the successful employment of the same compound for 

 the production of negatives, and many attempts [have been made 

 to produce in this manner a paper which might give results equal 

 to those of the process which is always known as silver printing, 

 and at the same time be so sensitive to light as to allow the image 

 to be impressed on it in a few seconds, instead of requiring an 



exposure often of hours The difficulty of procuring 



warmth of tone and consequent brilliancy in the picture seems 

 now to have been overcome in a new material which Messrs. 

 Marion, the photographic dealers of Soho-sqnare, have produced 



and are about to supply commercially The paper is 



obviously coated with a gelatine emulsion of some sort, and in 

 all probability rival experiments will before long find out its 

 precise nature. As regards the results producible by its means, 

 their value does not seem to admit of much doubt. 

 No industrial process can properly be termed successful 

 till it has stood the test of regular commercial work ; 

 but it is at all events safe to say thet no improvement of such 

 promise has been introduced into photography since the advent of 

 gelatine plates. . . . The whole process of producing a couple of 

 dozen prints need not take an hour. Allowing time for washing, 

 mounting, and finishing, an energetic man can, if required, supply 

 his customers with their likenesses the next day after the portraits 

 are taken. In these dark, short, winter days, it may be weeks 

 before a photographer gets light enough to print a batch of 

 pictures; but by Messrs. Marion's invention the whole thing can 

 be done by gaslight. The process of working the paper is quite 

 simple. As may be supposed, the image has to be " developed" — 

 that is, no visible image is produced by the exposure to light. 

 Consequently, the exposure has to be estimated, as it has in taking 

 a portrait or a view. The development is effected in very much 

 the same way as if an ordinaiy gelatine plate were under treat- 

 ment, the developer being a weak solution of ferrous oxalate. 

 After development the image is of a rich purple ; but as this 

 would change in the final, or ''fixing" bath, it is necessary to 

 " tone " the picture, as is done with an ordinary silver print, in a 

 solution containing gold. After this the picture is "fixed" in the 

 usual manner. Considerable variety of tone can be produced, the 

 tints ranging from a warm red brown to a purple or even black. — 

 Abridged from the Times of Nov. 24. 



Anti-Vaccination Curiosities. — The anti-vaccination craze is by 

 itself one of the most instructive and at the same time amusing 

 developments of nineteenth-century seutimentalism ; but it also 

 affords an unpleasant study in the sordid relations it is forced into 

 by those who promote it as a means of livelihood. Could we 

 entirely separate it from this connection, and regard it solely as 

 the possession of well-meaning but uninformed enthusiasts, it 

 would be possible to tolerate it without any very great feeling of 

 disgust ; but since the movement has been adopted, like its com- 

 panion delusion anti-vivisection, for merely trade purposes of 

 advertisement, it has necessarily become degraded from the level 

 it might easily occupy as a phase of eccentric mental activity. 

 We have recently been delur-ed with the literature of sub- 

 scription-loving agitators in reference to this subject, but the most 

 recent of these productions is so startling in its intention, and 

 so decidedly original in conception, that it almost deserves to be 

 rescued from the oblivion which is the usual fate of such emana- 

 tions. The communication is illustrated with the heading, " The 

 Government Censured;" but adherents of the Ministry will recover 

 from the momentary shiver induced by these ominous words when 

 they discover that the censuring body is the " London Society for 

 the Abolition," ic, which, it appears, recently assembled to pass the 

 following resolution : — " That the conduct of the Medical Depart- 

 ment in encouraging the profession to ignore vaccination os a cause 

 of death in certificates and at inquests ; and in their creation of 

 unnecessary panic during the slight prevalence of small-pox, with 

 the view thereby of inducing weak-minded persons to submit to 

 vaccination and revaccination, merits severe condemnation by 

 the Government." Accustomed though we are to the absurdi- 

 ties of conduct necessarily imposed on agitators who havejo 

 appeal for support to the unthinking and ignorant classes of the 

 population, still this precious idea of "censuring" the Government 

 strikes us as a master-stroke of policy. There are hundreds, nay, 

 probably thousands, of deluded parents who will accept it as a vital 

 blow to vaccination, and, in cnnsequeuce, will submit themselves, 

 their children, and their neighbours to the risk of infection, in the 

 mistaken belief that their " rights " are being defended with 

 success by the Society which receives their pennies. But its 

 most vicious effect will be found in the false feeling of security 



