Notes and Memoranda, 83 



two yards in length ; but they were afraid to attack them. M. Milne Edwards 

 recited numerous instances of the appearance of monster Cephalopods. — Eang 

 had seen one with a body as big as a hogshead ; and Steenstrup examined the 

 body of another, which was thrown on the shores of Jutland ; and which he de- 

 nominated Architeuthis dux. M. Milne Edwards considered there was reason to 

 believe that these large Cepha 7 opods were not all of the same species ; and he 

 had no doubt that many kinds, which existed in the depths of the sea, far ex- 

 ceeded the bulk of any known invertebrate animal. 



Arthtciaii Crystals. — M. Beequerel has succeeded in producing opals and 

 other crystalline minerals, in a short space of time, by strong currents of electri- 

 city. In order to succeed in these experiments, the solution must be pure, and 

 of a particular strength, while the intensity of the current must be regulated by 

 the. nature of the materials. From a solution of sulphate of alumina he obtained, 

 in the course of a few hours, a hydrate of alumina, like diopside, hard enough 

 to scratch quartz. In like manner he has hopes of ultimately producing topazes 

 and sapphires. 



Whi Otstees aee not eound in the Baltic. — The St. Petersburg 

 naturalists tell us that while oysters are found in the Mediterranean, the Atlantic, 

 the North Sea, and the northern parts of the Cattegat, they do not occur in the 

 Baltic, and refuse to be naturalized there. These facts are accounted for by the 

 small percentage of salt which the Baltic waters contain. The waters of the 

 Mediterranean contain 3 - 7 per cent, of salt ; those of the Atlantic, 3 to 3*6 per 

 cent. ; the north of the Cattegat, 1*8 to 2 per cent. ; while the saltest part of the 

 Baltic yields only T7 per cent, of salt. 



One-Chimney Houses. — "We find an account, in " Cosmos," of a plan of 

 making all the fires of a house communicate with one chimney. The stoves 

 employed are of a smoke-consuming kind, and the " unitary chimney " descends 

 to the cellar, where it is closed with a plug, which can be removed when sweep- 

 ing is required. 



The TTntveksaii Achromatic Miceoscope. — This is the name given by 

 Messrs. Smith, Beck, and Beck to a very valuable instrument upon a new plan, 

 and intermediate in quality between the ordinary educational microscopes, and 

 those of the first class. The form is peculiar, and evidently devised with greater 

 regard to facility of manufacture, than elegance of effect. It is not, however, bad 

 looking, and presents a combination of advantages not previously offered at so low 

 a price. A heavy ring of metal supplies a solid foot, and on one side rises a short 

 pillar, by which the body of the instrument is supported, and upon which it is 

 balanced, so that it can be inclined and fixed at any angle. The body is square, 

 but this does not affect the shape of the field, which is round as in ordinary pat- 

 terns. The eye-pieces are on Kelner's principle, having the field lens in the 

 focus of the eye lens, an arrangement which has the inconvenience of making any 

 particle of dust on the former exceedingly troublesome, but which possesses the 

 advantage of giving a large flat field, and of obtaining a given power from the objec- 

 tives with a shorter body than the usual Huyghenian eye-pieces require. The 

 objectives are two in number, of one inch and one quarter inch focal lengths. A 

 large and conveniently placed milled head moves the coarse adjustment, while a 

 lever, like those in Mr. Ladd's instruments, makes a fine adjustment, delicate 

 enough for all ordinary purposes. The mirror beneath the stage may be readily 

 placed so as to supply oblique light, and a condenser upon a jointed stem suffices 

 for opaque objects that do not require to be strongly lit. The stage is furnished 

 with a somewhat clumsy-looking but effective apparatus for holding slides, and 

 assisting their adjustment by hand, and is so made as to receive Wenham's para- 

 bola, the polariscope, or other additions which the purchaser may require. In its 

 simplest state this microscope will suffice for the generality of observations, and its 

 capacities may be brought up to a high standard by a small additional outlay. 

 We were particularly struck with the quality of the objectives : the quarter inch, 

 with the second eye-piece, enabled us immediately to exhibit both sets of lines on 

 the Plewrosigmaformosum, and we have no doubt it would resolve much more dif- 

 ficult tests. 



