172 



HAKDWICKE'S SCIENCE-GOSSIP. 



.part of ammonium sulphate, and 350 parts of distilled 

 water to form the silver solution. The reducing 

 solution to be made of I "2 parts of starch or grape 

 sugar, with three of caustic potash dissolved in 350 

 parts of distilled water (these parts all by weight). 

 When used, equal parts of the liquid are mixed 

 together and applied to the substance to be coated 

 with silver. 



Our vegetarian friends who encounter the objection 

 to their system, that we shall be deprived of leather 

 if they prevail, may be gratified to learn that in 

 -the last volume of the Chemical " Central blatt," 

 p. 798, is a paper on vegetable leather, by M. Bauer, 

 L. Brouard, and J. Ancel, who join in stating that 

 the following forms a very good substitute for 

 leather: 6 lbs. 10 oz. of gutta percha, 2 lbs. sulphur, 

 a\ lbs. raw cotton, 1 JTb. of zinc-white, 3^ oz. colcothar, 

 and 9 ounces of antimonic oxide. These are to be 

 vulcanised by steam. The essential constituents are 

 the gutta percha and sulphur ; the others may be 

 varied and replaced, according to the character of 

 -the leather required. This "vegetable leather" is 

 therefore a vulcanized gutta percha hardened by the 

 zinc, and toughened by the cotton. 



Good work is being done at the summit of the 

 British Isles. The Ben Nevis Observatory is in 

 full operation, winter and summer. The observers 

 have a remarkably quiet life during the winter, but 

 are now threatened with tourist invasion in summer 

 time, as the building of a hotel is contemplated. 

 Whether a climbing railway, like that on the Righi, 

 will be added, remains to be seen. Mr. Buchan has 

 already worked very effectively on the following 

 problems : 1st, the normal or average temperature 

 and barometric pressure for each month, and the 

 normal differences between these averages and those 

 at sea level ; 2nd, the daily variation of temperature 

 and pressure during each month ; 3rd, the daily 

 variation in the average velocity of the wind ; 4th, 

 variations of the wind as regards their general 

 prevalence over Scotland ; 5th, hygrometric observa- 

 tions, and observations of rainfall, and depth of 

 snow, &c. 



There are higher observatories in other countries, 

 but the isolated position of Ben Nevis, and its clear 

 .uprise directly from the sea, afford special facilities 

 for some of the most interesting observations. Its 

 geographical position, in reference to the Gulf Stream 

 .and polar atmospheric currents, also adds to the 

 interest and value of the observations. Present space 

 does not permit me to go into the results of these 

 observations, but I hope to return to the subject 

 hereafter. 



A very useful paper on the so-called "Wingless 

 Birds," fossil and recent, with a few words on birds 

 as a class, by Dr. H. Woodward, F.R.S., may be 

 found in the " Geological Magazine " for last month. 



PARASITICAL FLOWERING PLANTS. 

 By A. D. Webster. 



[Continued from p. 159-] 



THE dodders, of which there are three recognised 

 species, Cuscuta Europaa, C. epilinum, and C. 

 ipithynium, twine themselves around the stem and 

 branches of other plants, and become attached to 

 them by means of minute tubercles or suckers, and 

 thus attract from the system of the plant and air the 

 sustenance necessary for their own support. They 

 1 ossess the double power of germinating either in the 

 cap. ule or the earth ; in the latter case they adhere 

 to the round by the original root, drawing nourish- 

 ment therefrom until the young stem has fixed itself 

 to another plant, after which the original root withers 

 away. 



The dodders spread with terrible rapidity, and are 

 often a source of annoyance to husbandmen, especially 

 in the cultivation of leguminous crops. They destroy 

 the plants, either by deprivin ; them of their nourish- 

 ment or by strangling them in their folds. 



The greater dodder (C Europcta) is ; enerally to be 

 met with along the sides of hedges, and in neglected 

 ground, growing on brambles, nettles, and grass ; 

 also on flax, hemp, and clover. It is an annual 

 parasitical plant, with twining, thread-like stems of a 

 purplish-red colour, usually attaining a height of two 

 or three feet. The stem is much branched and 

 destitute of leaves, except here and there a small 

 membranous scale immediately under the branches. 

 The flowers, which are bell-shaped or globose, grow 

 in dense round clusters, of from ten to twenty in 

 each, are sessile, and of a whitish appearance with a 

 slight pinkish tinge. Rarely more than half-a-dozen 

 of the flowers are open at the same time, the lower 

 ones being not half developed when the upper are in 

 full bloom. 



Although said to be rarely found in Wales, this is 

 not the case, as I have frequently met with it and 

 more than once in large quantities. The plant being 

 of diminutive size and certainly not well known, may 

 account for the few districts from which it has been 

 recorded. On a farm near here, several fields of 

 clover last season suffered very severely from the 

 dodder, large patches here and there being quite 

 killed down by its encroachments. In walking over 

 the fields the dodder is readily recognised, from the 

 pinky appearance it gives to the half-withered 

 clover that is gradually becoming strangled in its 

 deadly embrace. The leaves of the clover on which 

 the plant is living first become covered with small 

 black spots or patches, gradually turn unhealthy, and 

 ultimately die back to the ground. The roots of the 

 clover do not appear to be injured. 



After examining the neighbouring plantations, 

 fences, and hedges, I came to the conclusion, that 

 in this case the dodder seeds were imported with 

 those of the clover, which, if correct, should make 



