114 



NATURE 



[June 4, 1903 



not larger than a pea, may be compared to the husk of a 

 hazel-nut in miniature. 



Both cupula and stalk bear numerous capitate glands, 

 some stalked, others sessile, which present the closest agree- 

 ment in size, form and structure with the glands which 

 occur on the vegetative organs of Lyginodendron. It is 

 the agreement between these glands, so close as to amount 

 to identity, that forms the basis of the attribution of the 

 seed to Lyginodendron. There is no other known plant 

 from the Coal-measures with glands at all similar, nor is 

 it likely that any unknown Gymnosperm should exactly re- 

 semble Lyginodendron in these characters. The vascular 

 strands which traverse stalk and cupule present the closest 

 agreement with those of Lyginodendron, and these and 

 other characters go to strengthen the conclusion drawn 

 from a comparison of the glands, and further support the 

 attribution. The evidence will, of course, be weighed by 

 botanists. Should it find acceptation, we have the follow- 

 ing position. Lyginodendron, a fern-like plant with certain 

 Cycadean characters, possessed seeds (on its leaves, so it 

 may be inferred from the structure of the stalk and cupule) 

 as fully characterised as those of any known Palaeozoic 

 gymnosperm. It retains, so far as its vegetative structure 

 is concerned, the intermediate position already assigned to 

 it, but whereas the fern-like characters have hitherto seemed 

 to preponderate, the discovery of the seed inclines the 

 balance strongly on the Gymnospermous side. The germ 

 of the present discovery dates from the time when it became 

 apparent on anatomical grounds that Lyginodendron was 

 a transitional type. Dr. Scott in his published writings 

 had already prepared the way, and the position now gained 

 is the logical sequel. Nor is it likely that Lyginodendron 

 stood alone ; we must be prepared to find, what has long 

 been recognised as a possibility, that many of the plants 

 grouped under Cycadofilices already possessed seeds, and 

 thus that a considerable proportion of the so-called "fern- 

 fronds " of the Palaeobotanist really belonged to seed-bear- 

 ing plants. The status of these " ferns " may be expected 

 to_ take many years to unravel, owing to the difficulties that 

 will be encountered in discriminating between such as bear 

 true fern-sporangia and those the sporangia of which are 

 really the pollen-sacs of Gymnospermous plants, and in allo- 

 cating the numerous impressions which are quite sterile. It 

 is premature to speculate how far back in the fern-series a 

 seed habit obtained, but the results of further investigations 

 in this field will be awaited with interest. 



"TABLOID" PREPARATIONS FOR 

 PHOTOGRAPHY. 



TTHERE is probably no one who has reason occasionally 

 to take_ a photograph, whether for simple pleasure 

 or for scientific or business purposes, without having at 

 command a well-equipped photographic laboratory, who 

 does not consider the preparation of the various solutions 

 required as a messy, troublesome and tedious performance. 

 And the getting of some of the chemical substances in a 

 fit state for use is a very real difficulty, only to be got over 

 in some cases by procuring the original packages or bottles 

 as issued by the manufacturer, and containing perhaps 

 twenty times as much as is required. We have known 

 several cases where so common a substance as sodium 

 sulphite has been obtained only after seeking for it at 

 several druggists, and other cases where the work was 

 spoilt by reason of the gross impurity of the material. 



These and similar difficulties are now matters of the past 

 for those who use the " tabloid " preparations of Messrs. 

 Burroughs, Wellcome and Co. Instead of a large bottle 

 of stuff awkward to manipulate because either the sub- 

 stance is in hard lumps or light feathery crystals, one has 

 a little bottle of little pills that need no weighing, because 

 the contents of each are indicated on the label. In the 

 majority of cases each tabloid has in it the quantity of 

 material needed for one ounce of solution, so that any bulk 

 can be made up without the possibility of error in calcula- 

 tion. The tabloids required are put into the measure glass, 

 water added, stirred a little or crushed with a glass rod, 

 and the solution is ready for use, with the advantage that 

 it is fresh, and made with materials that can be relied on. 



NO. 1753, VOL. 68] 



In many cases the requisite chemicals are mixed in the 

 one tabloid, sulphite, alkali, and bromide, for example in 

 developers, but there are no secret formulae, as the contents 

 of every tabloid are clearly set forth on the label. The 

 formula, if necessary, can be modified to any extent by 

 adding to it a tabloid of one or the other ingredients ; or, 

 if preferred, tabloids of simple unmixed substances may be 

 used throughout. 



So far as variety goes, practically everything that is re- 

 quired in photographic practice is supplied, including even 

 such rarely used chemicals as potassium percarbonate and 

 ammonium persulphate. There is a large selection for 

 making gold baths for the toning of prints, and potassium 

 ammonium chromate is supplied in 24-grain tabloids for 

 sensitising carbon tissue. Ferrous oxalate and mercuric 

 chloride are the only two omissions that we note ; perhaps 

 there is some difficulty with regard to these. 



It appeared not unlikely that some of the chemicals 

 might show signs of deterioration from their manipulation 

 in the preparation of the tabloids, but those that we have 

 tested have proved unexceptionable in quality. These prepar- 

 ations are worthy the attention of even the best equipped 

 photographer working at home in his own laboratory, 

 particularly with regard to the chemicals that are rarely 

 required. 



A NEW INDEX OF APPLIED SCIENCE. 



WE have received a copy of the first issue of a new 

 monthly periodical ' published at Brussels. The 

 title. Index of the Technical Press, appears on it in the 

 three languages French, English and German. The 

 object of the publication is to supply a monthly index of 

 articles of general interest appearing in the technical Press 

 throughout the world, and giving the title with a brief 

 explanation, the name of the author, the origin, the date 

 of publication, and the length. In the case of articles 

 appearing in the English, French, and German papers, these 

 details are given in the languages in which they originally 

 appeared. In the case of articles printed in other languages 

 they are translated into French. 



One very good characteristic of the publication is that it 

 is printed on one side of the paper only, and in a convenient 

 form for cutting out and pasting on cards for use in con- 

 nection with card indices. 



The publishers undertake to supply cuttings from the 

 original papers of most of the articles indexed, at prices 

 indicated by a letter affixed to each entry. Translations can 

 also be obtained on a fixed scale. Such a publication should" 

 be of considerable value if the scheme is carried out with 

 completeness, and the subscription price of five francs per 

 annum is not a heavy one. Much, however, will depend on 

 the interpretation given to the expression " general 

 interest." 



The greater part of the issue is taken up with entries of 

 engineering articles under various headings ; some of these 

 cover rather a wide field — electrical engineering, for ex- 

 ample, forms one of the sections, without any subdivisions. 



Besides engineering articles, there are sections devoted to 

 statistics, political science, political economy, law, legisla- 

 tion and jurisprudence, administration, constabulary, in- 

 surance and partnership, commerce, communication and 

 transport, mathematics, astronomy, physics, chemistry, 

 geology, medicine. Various trades and manufactures are 

 also included. 



The " brief explanation " promised is confined to very 

 slight extensions of the title in some cases, so that the 

 only guide to the value of an article is the name of the 

 author and that of the paper from which it is taken. This, 

 however, if the indexing is really comprehensive, should be 

 of considerable value, more especially with regard to subjects 

 in which systematic abstracts are not obtainable. 



Rather numerous errors are made in printing the English 

 and German entries, especially in the former. They are not' 

 of a character to cause any inconvenience to those familiar 

 with the languages, but they are unsightly, and their 

 occurrence might easily be obviated by the employment of 

 a proof reader familiar with the languages. 



G. W. DE T. 



1 /ntie.r of the Technical Press. (20 Rue de la Chancellerie, Brussels.) 



