38 



NATURE 



[May ii, 1 88: 



markable finish and value. The object is then heated, 

 enamelled, and baked. 



It is different with the decoration accomplished by 

 means of a muffle oven ; in this method the painting is 

 always made on baked porcelain, and consequently on 

 enamel, and the heat employed is relatively low. In this 

 process there is necessary, in order to make the colours 

 on the metals adhere, a medium, which is called the 

 fondant ; it is generally a silicate, or silico-borate of lead. 

 By raising the temperature, these bodies are fused, attack 

 the object, combine with it, and at the same time deter- 

 mine by that reaction the adhesion of the colour. Ac- 

 cording to the nature of the fondants and colours, a 

 greater or less heat may be applied ; and as certain 

 colours are more sensitive than others, it is frequently 

 necessary to bake at successive fires of different tem- 

 peratures. The baking of colours by this process re- 

 quires very great experience ; the absence of any instru- 

 ments of precision is greatly felt, and there is no other 

 means of ascertaining the temperature that prevails in 

 the muffle, than to observe on samples of porcelain the 

 changes of colour which are undergone by certain pre- 

 parations very sensitive to differences of temperatures. 



PHYLLOXERA 

 "p\R. MARION has recently published (Dupont, Paris, 

 -'-' 1 882) a rt'sunu' of the results attending the efforts 

 of the Paris, Lyons, and Mediterranean Railway Company 

 to stay the ravages of phylloxera. These efforts were 

 inaugurated in 1S76 at a time when the wine growers of 

 Herault were on the point of relinquishing the struggle. 

 Dumas having demonstrated the great value of alkaline 

 sulphocarbonates as insecticides, this company energeti- 

 cally planned and organised its distribution, with such 

 success that in the period between 1S77 and 1881 the 

 number of barrels distributed through their agency rose 

 from 10S5 to 14149. The sulphocarbonate is injected 

 twice a year in doses of 1 2 grammes into holes half a 

 metre apart, being either administered in simple doses or 

 double doses, with an interval of three or four days. The 

 ■doses vary, however somewhat, according to the nature 

 of the soil and condition of the vines, and much is there- 

 fore left to the intelligence of the operator. The remedy 

 acts imperfectly in clayey or stiff soils, and when the 

 ground is saturated. 



The first injury manifested when vines are attacked 

 is the loss of their finer radicles, which perish through 

 the suction of the aphid. The consequent loss of nutri- 

 tion next causes the partial death of old wood and 

 feebleness in the young shoots, followed by a gradual 

 diminution in the fruit. If badly attacked, old vines 

 cannot be saved, as much of the woody stem is dead 

 beyond recovery, but young vines almost always recover 

 under the sulphocarbon treatment, when applied under 

 favourable conditions ; new radicles appear, then an in- 

 creasing luxuriance in the foliary organs, and finally the 

 renewed production of fruit. Dr. Marion strongly advo- 

 cates the use of this remedy, and sustains his arguments 

 by well selected examples which thoroughly demonstrate 

 its efficacy. It is capable of a wide application, the prices 

 realised for wines in most districts being well able to 

 support its cost. 



Other remedies found practicable, but not discussed 

 in Dr. Marion's work, are submersion, and replacement by 

 American stock, with or without grafting. The former 

 can only be practised in comparatively flat or low-lying 

 vineyards in proximity to rivers or canals. These are 

 surrounded by strong embankments of from one to one 

 and a half metres high ; and the waters are either let in 

 by mere difference of level at flood times or by centrifugal 

 pumps. The water must not be less than 40 to 50 centi- 

 metres in depth, and remain forty to fifty days, and the 

 process is repeated each year. Some waters help to 



fertilise the soil, and this treatment has invariably pro- 

 duced the best results. 



The introduction of American vines has also in certain 

 districts been attended with great success, both in clayey 

 soils, and where the smallness of the vintage per acre 

 precludes the sustained use of costly remedies. The 

 species, however, possess most varying powers of resist- 

 ance in different soils, and require to be selected with 

 great care. In the vineyards of Medoc, and of high- 

 class vines generally, American stocks are only used for 

 grafting, a clever workman being able to operate on 100 

 to 200 vines per diem, 70 to 90 per cent, of which will be 

 successful. 



Among partly successful remedies may be mentioned 

 the system Garros. This consists in uncovering the roots 

 of the vines as far as possible, and treating them with a 

 litre of powdered quicklime, sulphate of copper, and sea- 

 salt. The remedy has been found efficacious, but seems 

 to act, not fatally, on the insects, but in diminishing their 

 number and stimulating the plants to overcome their 

 ravages. The system Sabate is directed towards the de- 

 struction of the winter egg, which produces the winged or 

 reproducing stage of the phylloxera. The treatment 

 consists in removing the dead bark from the trunk, and 

 dusting with powdered quicklime, but, like the last, it is 

 not fatal to the insect. A third remedy, that of Dunay, 

 consists in exposing the roots of the vine, and coating 

 them from the surface-roots to some 20 centimetres in 

 depth with coal-tar. 



I saw, while staying with Leland Cossart, in Madeira, 

 a plan somewhat similar to this practised with great 

 success. Mr. John Leacock, its inventor, removes after 

 the first autumn rain, the soil to a depth of some 20 

 inches, so as to expose the upper roots, peels off the loose 

 bark and paints the roots with resin dissolved in turpen- 

 tine, at the same time manuring the vines. This mixture 

 being unaffected by water remains viscid for three or four 

 years, and destroys the insects on their passage up and 

 down. Its cost is less than a halfpenny per vine, and 

 while those so treated were luxuriant in bright green 

 foliage, all around were yellowing and weak. 



J. S. Gardner 



THE EXTENSION SEAWARD OF THE 

 WATERS OF THE CHINESE RIVERS 

 T'HE following notes, on the extension seaward of the 

 1 waters of the Yang-tse, were made in the months 

 of September and October (1878), a period of the year 

 when the river first commences to fall, after its waters 

 have attained their maximum height. The four points to 

 which I turned my attention were — the colour and general 

 appearance of the water, the taste, the specific gravity, 

 and the relative amount of chlorides in solution. Owing 

 to the powerful revolving tides of the estuary of the Yang- 

 tse, the river-water and sea-water are churned up to- 

 gether in such a manner that the patches of green and 

 yellow water may be plainly observed, and their line of 

 union as sharply defined. It is from this cause that the 

 density of the water may fluctuate to a very marked de- 

 gree in the limit of a single mile ; and it was not an uncom- 

 mon experience, on passing from a patch of yellow water 

 into one of green colour, to observe a sudden increase in 

 the density from 1005 to 1-015. The specific gravity is 

 never constant in the same locality ; and it is only by 

 taking all the four points into consideration that a reliable 

 inference could be drawn : thus, the first evidence of the 

 proximity of salt water, which was found at a distance 

 varying from fifteen to thirty miles from Wusung, was 

 not afforded by any marked increase of the density or by 

 any alteration in the taste or colour of the water, but 

 merely by a very perceptible increase in the amount of 

 chlorides held in solution ; whilst in the midst of the 

 islands of the Chusan archipelago, which are removed 



