222 



HARDWICKE'S SCIENCE-GOSSIP. 



tbat many granules, and perhaps entire samples, of 

 wheat do not, except with a very high power, and 

 even then its polarization is much less distinct than 

 that of other kinds. 



Rice I have found uniformly to polarize, and in 

 its case the error has probably arisen solely from a 

 neglect of employing a sufficiently high power 

 necessary for its examination. It appears to be a 

 popular error that the polariscope cannot be advan- 

 tageously used with the higher powers of the micro- 

 scope ; but my own experience is that many starches 

 cannot be properly examined with a lower power 

 than the ■£$, and the polariscope can be just as 

 easily and correctly used with it as with any lower 

 power objective. The interposition of a selenite 

 produces not only a pretty effect, but often shows 

 up peculiarities of form in the granule, and it is 

 well to examine an object under all aspects. 



The well-known and beautiful effect produced 

 upon starch by iodine is of the greatest value to 

 the microscopist. The application of a very weak 

 solution of iodine in iodide of potassium, part of a 

 drop of which is allowed to run (if from the aper- 

 ture of a Highley's microscopic test-bottle, so 

 much the easier to manipulate) under the thin 

 cover of the suspected substance while under ex- 

 amination in the microscope, will at once detect 

 with certainty the presence or absence of starch by 

 the blue colour imparted to the granules, even 

 when the granules are so minute that the unaided 

 eye cannot perceive the colour, and where the 

 transparency of the granules would prevent their 

 being noticed by the microscope alone. 



The value of this easily-applied test, in conjunc- 

 tion with the microscope, for the detection of food 

 adulteration, as of butter, mustard, pepper, and a 

 host of other of the commonest articles of daily 

 onsumptioD, cannot be too well known. 



Much might be said about the varied effects of 

 temperature on starches if it came within our pre- 

 sent province. Starch is usually said to be in- 

 soluble in cold water, and for the most part truly, 

 though it probably applies to the cellulose only ; 

 for if the granules be ground up with fine sand in 

 cold water the cellulose membrane is ruptured, and 

 the solubility of the granulose shown by its expan- 

 siveness. 



In conclusion, just a word as to the mounting 

 and preservation of starches as microscopic objects. 

 Whether any known process of mounting will 

 render them permanent is disputed. My own 

 limited experience on this point is that if the 

 granules be dried without heat they can be well 

 preserved in balsam, after the mixing putting in 

 turpentine ; they have kept good in this way for 

 twelve months, and without any appearance of 

 their becoming impaired in any way. 



Glycerine in any form is unsuitable, from its 

 solvent properties. If others can attest to the 



permanency of starches mounted in balsam, or by 

 other means, a lasting collection of a very interest- 

 ing kind can be made in a useful field of micro- 

 scopical study, and one but little explained. 



I. C. Thompson. 



HOLIDAY RAMBLES IN THE WEST.OF 

 IRELAND. 



The Plants and Rocks of Aran, 

 by g. h. kinahan, m.k.i.a. 



f\ N these islands the geology and botany are very 

 ^ similar to those in the Burren, co. Clare. 

 Most of the surface of the islands is bare lime- 

 stone-crags, that rise in huge steps from the east 

 and N.E. shores ; while the western coasts are 

 perpendicular cliffs cut by the tidal waves of the 

 Atlantic. The surface of the islands is thus de- 

 scribed by O'Flahertie : — " The soile is almost 

 paved over with stones, soe as, in some places 

 nothing is to be seen but large stones with wide 

 openings between them, where cattle break their 

 legs. Among these stones is very sweet pasture ; 

 so that beefe, veal, mutton are better and earlyer 

 in season here then elsewhere." The islands are 

 still famous for their good and fat cattle. In the 

 coves, bays, and strands vast quantities of seaweed 

 are cut in May and November, the latter crop being 

 principally used for manure, while the May crop is 

 dried and burned into kelp. To save the seaweed, 

 the Aranites have to keep a number of ponies. 

 These, however, after the May weed is all drawn 

 up, are shipped to Hiarconnaught, where they 

 grass during the summer, except on Sundays, when 

 the Hiarconnaughtites collect them, at least the 

 best of them, from the mountains, and run races 

 with them. 



Erom the following list it will be seen the rare 

 plants are very similar to those in parts of the 

 Burren : — 



Bare Plants in Aran. — Ajuga pyramidalis, As- 

 tragalus hypoglottis, Helianthemum canum (Rock 

 Rose), Viola hirta (Hairy Violet), Cornus sangui- 

 nea, Arundo epigejos, Lavatera arborea (Tree 

 Mallow), Matthiola sinuata (Sea Stock, Straw 

 Island), Arabis ciliata, Cerastium arvense (Field 

 Mousear), Alsine verna, Geranium sanguineum 

 (Bloody Cranesbill), Pimpinella magna, Asperula 

 cynanchica, Rubia peregrina (Wild Madder), Adi- 

 antum (Maidenhair Fern). 



In parts of the islands there are acres of the 

 Adiantum ; while in the neighbourhood of the 

 ecclesiastical settlements are colonies of introduced 

 plants, many of which are herbs or have medical 

 qualities. 



Among the limestone, which is a marked differ- 

 ence between it and that of Burren, there are thin 

 beds of shales, clays, and clunch. These are most 



