442 



SCIENTIFIC NEVS^S. 



[May II, i8 



tion of buildings. It is also tolerably certain that all or 

 nearly all the poisonous organic matter is destroj'ed. 

 Doubtless so much of it as comes in actual contact with 

 the flame is burnt and effectually destroyed ; it is also 

 probable that so much of it as comes in contact with 

 metal surfaces heated to 400*^ or 500° Fahrenheit is also 

 oxidised, and therefore rendered harmless ; the only 

 doubtful portion, therefore, is a small proportion of the 

 sewer-gas which travels upwards at a high velocity, and 

 may neither touch the flame nor the heated grating 

 above the burner. Even if it escapes contact in this 

 way, its temperature must be considerably raised, and for 

 all practical purposes there can be little doubt that all 

 deleterious matter is removed from the sewer-gas. 



The usual method of ventilating sewers by means of 

 gratings in the roadway is not only disgusting, but in- 

 jurious. On the other hand, mere ventilating columns 

 or pipes cannot be relied on, as they are so easily 

 affected by varying conditions of the atmosphere. It is 

 decidedly a right idea to insure a regular discharge, as 

 there is then a constant ventilation of the sewer, and if 

 at the point of discharge the organic matter, which is 

 the carrier of disease germs, is destroyed, the system 

 leaves little to be desired. The invention now under 

 notice has been introduced by Mr. Stephen Holman, 

 C.E., of 15, Great George-street, London. 



MARINE EXPLORATIONS IN THE 

 ADRIATIC. 



THE explorations conducted by Professors Julius 

 Wolf and Joseph Luksch during the years 1874 to 

 18S0 have been summarised by Captain Rottok, and 

 published in abstract in Humboldt. These researches 

 include determinations of temperature ; of specific 

 gravity and proportion of salts; of the transparency and 

 the colour of the waters and of the currents. 



Observations of temperature were made at more than 

 150 stations, both on the surface and in depths. The 

 temperature on the surface and in the immediately 

 subjacent layers of water increases in summer on the 

 Italian coast, and along the axis of the sea by 2° to 3° C. 

 from north-west to south-east. It was also found that 

 the water on the western side was warmer than on the 

 eastern. The decrease of temperature from the surface 

 to the bottom is, at first, as is usual, rapid, and amounts 

 to 10° C. for the first thirty fathoms. Then it becomes 

 very slow, and is only 2° C. as far as eighty fathoms. 

 On the bottom the temperature generally follows the 

 relief of the ground. Only in the north-eastern part of 

 the Adriatic there prevails a temperature which is very 

 low in proportion to the depth. From this circumstance, 

 viewed in connection with the small specific gravity of 

 the lower strata of water, we may infer the existence of 

 cold springs at the bottom. A constant temperature is 

 found only in the very largest strata. In winter the 

 distribution of the temperature in depth is different from 

 and more uniform than thatobserved in summer, probably 

 in consequence of the more active vertical circulation. In 

 the cold season the differences of temperature were 

 much slighter than in summer. Sometimes there was 

 even found a slight rise of temperature on descending, 

 or, at any rate, a uniform heat. Spring and autumn 

 formed naturally periods of transition. Spring, however, 

 retains the char.Tcte-- of theptist winter, as the perpendi- 



cular variations of temperature are feeble and slow. 

 Autumn approximates more to the character of summer 

 in a rapid perpendicular decrease of temperature. 



The observations on the specific gravity of the water 

 and the proportion of saline matter in solution were less 

 numerousthan the determinations of temperature. Still, 

 they sufficed to show the general character of the density 

 of the water. 



Like the temperature, the salinity of the water on the 

 surface increases in summer from the north-west to the 

 south-east, but, contrary to the temperature, it is greater on 

 the Dalmatian than on the Italian coast. 



The distribution of saline matter in respect to depth 

 is very irregular, as might be expected, from the different 

 currents, the entrance of rivers and springs and other 

 local conditions affecting such a narrow sea. In general, 

 the proportion of salt increases from the surface to the 

 bottom, but the increase is very unequal, and sometimes 

 interrupted by a decrease. In the winter, observations 

 were made only at Quarnero, and the result showed a 

 much more uniform distribution of saline matter than in 

 summer. 



The transparency of the water was determined by 

 immersing polished or painted discs of metal. In the 

 two series of observations made, the depths at which the 

 discs ceased to be visible were between thirteen and 

 twenty and a-half fathoms. 



The colour of the Adriatic is dark blue by transmitted, 

 and intense blue by reflected light. 



The surface-currents were determined, not by direct 

 measurements, but indirectly from the observed distri- 

 bution of heat and salinity, taking into account the 

 meteorological relations, the access of fresh water from 

 the shore, the configuration of the bottom, and the rota- 

 tion of the earth. Direct measurements gave no 

 satisfactory results, since the results were interfered with 

 bj' other factors. 



The ordinary supposition that there occurs along the 

 coasts of the Adriatic a circular rotation of the water in 

 the opposite direction to the hands of a watch was con- 

 firmed. Along the western coast a mass of water, poor 

 in salts, flows towards the south-east, approaching, as it 

 advances, more closely to the shore, becoming also 

 narrower and deeper. A current of more saline water,com- 

 ing from the Mediterranean Sea, runs along the Dalmatian 

 coast in a north-western direction. It is, however, often 

 diverted from its course by the numerous islands. Thus 

 at certain points branches of the current turn off to the 

 west, and then to the south-west, uniting with the 

 counter-current on the opposite coast. 



The Phenomena of Zymotic Disease. — The opinion 

 is now gaining ground that the so-called " disease-germs" 

 do not occasion fevers, etc., by their own mere presence 

 in the blood, but by certain definite chemical compounds 

 which they produce. These bodies ultimately prove 

 fatal to the germs themselves — a phenomenon by no 

 means unexampled. This view likewise explains why 

 any animal which has once recovered from such a 

 disease is generally, for a term of years at least, proof 

 against a second attack. It is even suggested by MM. 

 Chantemesse and Vidal, that the peculiar compounds 

 elaborated by such microbia may be isolated, if not per- 

 haps artificially manufactured, and may serve to render 

 man refractory to the attacks of disease-germs. — Journal 

 des Dchats. 



