HARDWICKE'S SCIENCE-GOSSIP. 



255 



Diadelphia decandria = Papilionacear), have but little 

 affinity with each other. They must therefore be 

 forced into these unnatural groups, and retained there 

 by an effort of memory, instead of falling into order 

 as it were of their own accord and being pictured on 

 the mind in groups of well-defined resemblance. 



I have known a very fair general knowledge of 

 plants to be gained in one year by observing each 

 kind of flower as it opened, whether wild or in the 

 garden, and entering its name, however obtained, in 

 a book, with the date and its natural order at- 

 tached. By this means a familiarity with the general 

 characters and appearance of the larger orders is 

 soon acquired and a basis is laid by general obser- 

 vation, from which more particular study naturally 

 and easily follows. The number of orders seems 

 large to a beginner, but of the ninety-two which com- 

 prise British flowering plants twenty- three or one- 

 fourth of them have only one native species each. 

 Again, taking the "Student's Flora of the British 

 Islands," there are in all 1221 species of Phanero- 

 gams, or, leaving out sedges (86) and grasses (102) 

 1032, more than half of which (532) are included in 

 ten orders thus : — 



1. Compositje . 



2. Leguminosae 



3. Cruciferae. 



4. Caryophylleae 



5. Umbelliferas . 



106 

 67 

 56 



55 

 54 



6. Scrophularinese . 44 



7. Labiata; .... 42 



8. Rosacea? ... 42 



9. Orchideas- ... 37 

 10. Liliaceae ... 29 



If we examine this short list we shall see that the 

 marks of the orders are so distinct that with very 

 little practice no mistakes can be made ; some 

 obvious if not conclusive characters are seen at a 

 glance. A Composite is distinguished at once by its 

 llowerhead of florets having united anthers ; the 

 Leguminosce, represented in Britain only by the tribe 

 Papilionacese, are separated from all others by the 

 form of their flowers ; the Cruciferae are recognised 

 by their cruciform flowers and tetradynamous 

 stamens ; the Orchideoe alone are gynandrous. And 

 so the learner goes on to notice obvious marks of 

 orders, which are most easily impressed on the mind 

 by writing down the name of each plant together with 

 the name of the order to which it belongs. While 

 familiarity with the orders is being acquired groups 

 of species by degrees fall into their place as genera, 

 and the student instead of beginning with " This is a 

 Crucifer," says " This is a Brassica" ; instead of" This 

 is one of the Caryophylleoe," " This is a Cerastium," 

 and so on. Before so much as this is learnt any 

 British Flora will be used without difficulty, but the 

 one which is the most recent, and contains the most 

 information in the least space, is Hooker's " Student's 

 Flora of the British Islands." 



R. H. A. 



Heracleum. — Heracleum Sphondylium is called 

 " Dryland Scout " in the neighbourhood of the Rock, 

 co. Tyrone. — S.B. 



MICROSCOPY. 



Your correspondent J. T. G. (in No. 169, p. 213) 

 thinks "that the microscope might be used for more 

 practical purposes than is usually the case, as, for in- 

 stance, in the study of wool, its nature, quality," &c. The 

 microscope can be so used, more than it " usually " has 

 been, to the advantage both of the user and of the 

 commercial and scientific worlds. As a learner, J. T. G. 

 cannot select a more promising or worthy subject for 

 study, and he should be encouraged to persevere, 

 until he masters his selected speciality. J. T. G. is 

 evidently unaware of what has already been done and 

 published on this subject. There is an elaborate 

 work in German (" Das Woolhaar," by H. Malthusius, 

 von Grunow) on the microscopic character of wool. 

 In English, a report by Dr. J. J. Woodward, Professor 

 J. L. Le Conte, Dr. J. G. Hunt, and Dr. E. M. 

 Schaeffen to the secretary of the United States 

 Treasury on "The Scientific Examination of Wool and 

 Hair." Bulletin of the National Association of Jfooi 

 Manufacturers, vol. v. No. 7— Boston, 1875, which is 

 the best thing in English— perhaps in any language to 

 my knowledge. "Asa learner," J. T. G. is in a 

 "difficulty as to the manipulation of the instrument." 

 It is hardly to be supposed that he would undertake 

 such a study until he had learned the uses of his 

 tools. The manipulation of the instrument for this 

 study is the same as for any other study. As I have 

 done something at it, I will give a few hints on the 

 manipulation of the wool and hair. The fibres 

 whether unmanufactured or from fabrics should be 

 well washed — clean— free from dirt and grease ; 

 alkalies or soap may be used, and also alcohol or 

 ether. It will be well to examine also the uncleaned, 

 t o learn if the cleaning agent produces any effect or 

 change in the fibres or scales. In case of dyed 

 fabrics it is sometimes needful to discharge the 

 colouring substance in order to render the fibres 

 sufficiently transparent. A T 4 S objective of the highest 

 grade I have found the most useful power, supple- 

 mented by an immersion |th of equal quality for 

 special cases. A few fibres may be placed on a slide 

 in water for preliminary investigation. For permanent 

 mounts, glycerine or glycerine jelly I have found the 

 best medium. (I hope J. T. G. will find something 

 better.) The slides that have been mounted some 

 weeks or months seem to show the peculiarities of 

 the fibres better than when freshly mounted. The 

 above hints may be of service to the inquirer. All 

 the rest he must search for himself : be an original 

 investigator, not take anything second-hand from any 

 authority, however high its reputation may be ; 

 verify by observation all statements of fact or theory. 

 If he will do this, he can in the course of three or four 

 years make valuable contributions to science and com- 

 merce, and be able to answer his own questions 



