49 8 



SCIENTIFIC NEWS. 



[Nov. 16, 1888. 



out when red hot. A hair-like thread is thus formed, 

 which, however fine, remains tubular, as may be proved 

 by breaking it asunder, placing the fine end under water, 

 and blowing through the original undiminished tube. A 

 small cloud or stream of minute air bubbles is thus blown 

 into the water. 



Markownikoff cuts up such hair-like tube into short 

 pieces from g to § of an inch in length, seals up one end, 

 which is easily done by holding it for a moment in a 

 flame either before or after cutting it off. A few of these 

 minute open-mouthed bottles, each containing a micro- 

 scopic elongated air-bubble, are dropped into the liquid, 

 which then boils gradually and without violence, the 

 steam bubbles proceeding from these nuclei. 



Tomlinson, who long ago studied the subject of nuclei, 

 showed that minute air-bubbles are the most effective, 

 not only in promoting ebbuliton, but also in the opposite 

 action of initiating solidification. Thus, clean water that 

 has been previously boiled, or water free from solid or 

 gaseous particles, may be brought down considerably 

 below the freezing point without freezing, if it stands 

 undisturbed in a smooth vessel ; but if a solid particle 

 be dropped into it, and that particle has air adherent to 

 it, or forces a little air down with it, crystals of ice are 

 instantly formed. Supersated solutions of crystalline 

 salts behave in the same manner ; many of them very 

 strikingly. This is notably the case with sulphate of 

 soda. 



The familiar experiment of stirring champagne with a 

 piece of bread after ordinary effervescence has ceased, 

 and thereby renewing it, is an example of this action of 

 gaseous nuclei, the efficiency of the bread depending on 

 its porosity and the air contained within its pores. 



On one occasion I assisted at a Scandinavian mid- 

 night revel in the ancient capital of the Vikings. We 

 emulated those Vikings by repeating their drinking 

 ceremonies. When the bumpers were all adjusted, each 

 man rose, thus with the others forming a circle round 

 the table, each lifted his tall glass by the stem, raised it 

 over head to full arm's length, then each reached forward, 

 clashing all the glasses together in the centre of the 

 circle and yelling out " skaal," in chorus to the clang. 

 The liquor was champagne in the old-fashioned, tall, 

 narrow glasses ; much was spilled at the skaal, and the 

 sparkling of what remained in the glass was much 

 abated. Then the Norsemen performed a curious ex- 

 ploit. They rested their glasses on the table, upraised 

 their outstretched hands, and brought down the palms 

 with a heavy thump upon the mouth of the glass. This 

 was immediately followed by a superficial re-effer- 

 vescen':e that covered the surface of the wine with a 

 head of white foam. 



I repeated the performance and studied the pheno- 

 mena, and found that, when thus struck and pressed, the 

 flesh of the palm bulged downward into the glass, and 

 sensibly rested upon an elastic cushion of compressed 

 air. It had acted like the pressing of a piston into a 

 closed cylinder, and evidently drove some of the air 

 into the liquid at its surface, where the new effervescence 

 occurred. 



These and other facts that might be specified 

 justify the conclusion that the action of MarkownikofFs 

 little tubes mainly depends upon the little measure of 

 air they contain, though in the abstract I have read 

 (Journal of the Chemical Society, November, 1888, page 

 1,155) no sucn explanation is suggested. 



The abstractor, B. Brauner, adds that he has tried the 



device, " and found it invaluable, especially for the 

 distillation of concentrated acids." 



I should add that a short capillary tube with one end 

 closed retains the air it contains with curious tenacity, 

 and that it is probably condensed therein very consider- 

 ably by its adhesion to the walls of the tube. A larger 

 tube thus filled with air and immersed in a liquid with 

 mouth upwards, is speedily filled with the liquid, the 

 air bubbling into the water. Not so the short capillary 

 tube. Strive as you may you cannot fill it with water 

 if dry air has once taken up its quarters within it. 



■ ■>-J»t^»*3«f-* 



THE MARINE ZOOLOGICAL STATION 

 AT ALGIERS. 



p\R. CAMILLE VIGUIER gives in La Nature an 

 account of this institution, interesting as being the 

 first of the kind established on the Southern or African 

 shores of the Mediterranean. It occupies a small plot 

 of ground on the peninsula of the Admiralty, and the 

 building is shown in the accompanying illustration (fig. 1), 

 for which we are indebted to the courtesy of the publishers 

 of La Nature. It has the disadvantage of a close proxi- 

 mity to the coaling-station of the navy, so that there can 

 be no windows upon this side up to the level of the first 

 floor. This deprives the laboratories of the north light, 

 well known to be the most favourable for microscopic 

 work, and compels the tanks to be placed on the south 

 side. It has, however, the advantage of proximity to the 

 city, and of thus enjoying a regular supply of fresh 

 water and of gas. The water is at a pressure sufficient to 

 rise to the level of the terrace. The gas is distributed 

 throughout as a source of heat, and, if needful, of light, 

 and it furnishes besides the motive force necessary to 

 pump sea-water and to drive the small dynamo which 

 ordinarily supplies light to the whole establishment. Sea- 

 water is taken, in ordinary weather, from the open 

 sea, and a rotatory pump forces it into two reservoirs on 

 the terrace. Thus salt water is distributed throughout 

 the station at a pressure which in the tanks of the base- 

 ment exceeds one atmosphere. 



Though thus supplied from the open sea, the station is 

 in the harbour, sheltered from the waves, and boats can 

 always be used, except in extraordinary weather. The 

 fishermen already begin to bring in curious animals 

 which they find, and which are not marketable, and 

 probably in this way interesting specimens will be 

 secured. 



The building contains cellars, stores, the machinery, 

 and on the south side a long sink which can receive tanks 

 of all shapes, fed at will either with fresh or salt water. 

 This room is sufficiently illuminated by lights made 

 obliquely in the masonry, in which are lodged the large 

 tanks of the ground floor. The tanks on the ground 

 floor are about a cubic metre in size, and are attended 

 to from without by means of an iron gallery, reached by 

 stairs. They are protected by means of glazed frames 

 shaded by blinds. These tanks, fitted with rock-work, 

 like the external tank, are so transparent that it has been 

 possible to photograph a new Alcyonaria. All the tanks 

 can be illuminated from without by means of an arc 

 lamp, which serves for microscopic photography. The 

 first floor is devoted to laboratories and a library. 



As the establishment has not been created for the 

 amusement of the public, and as the. tanks are destined 



