238 



KNOWLEDGE. 



rOcTOBEK 2, 1899. 



northern sky from the south of England, and took a long 

 horizontal course from about north-west to north-east. Lieut- 

 Col. Boileau, of Trowbridge, describes the path as directed from 

 Ursa Major, afterwards passing above Capella and through 

 Perseus towards Algol. Jlr. J. L. Whittle, of ]\Ianchester, 

 estimated that the meteor was half as bright as the moon, and 

 describes its course as frota Deneb Cygni to Aquarius. It was 

 also seen at Oswestry, Birmingham, Bristol, &c., but the obser- 

 vations are not sufficiently exact to indicate the radiant 

 accurately. This point was situ,ated in Ursa Major, and further 

 descriptions of the visible path of this fine meteor would be very 

 valuable in aiding to fix the position definitely. 



Other large meteors. — The following have recently been 

 recorded : — 



Oate. Time. Ka^. a 5 a 5 



b. m. '' o o 



August 27 ... 9 15 9 216 -^38J to 201J-H32J Slow. W. E. Besley, 



Loudon, S.W. 

 „ 28 . . 9 30 11 .lOaj-HSJ to315i— 5 Slow. Train. W. E. Besler. 



London. S.W. 

 „ 28 ... 12 3.5 Full }) 292J-H1" to 301 + 3 Slow. Train. W. E. Besley, 



London. S.W. 

 Sept. 2 ., 12 -1 3x9 40 -H67 to 37 -K74 Swift. Streak. VSr.P.D., 



Bristol. 

 4 ... 8 13 ? 220 -H 35 to 217 +25 Slow. A.S.Williams, 



HoTe. 

 4 .. 8 14 21 397-1-28 to 296 -US Swift. Stre.ik. T. H. 



Astbury, Wallingford. 

 8 .. 8 2X »9 313 + 4 to 287 + 4 Slow.Traiu.T. H.Asflmry, 



Wallingford. 



The last of these meteors was also seen by Mr. A. King, of 

 Leicester. It belonged to a radiant at 347° -*• S", and appeared 

 over the English Channel and south of England, descending 

 from seventy-one to twenty-six miles during a visible flight of 

 one hundred and fourteen miles. 



Additional observations of these objects would be very useful. 



In October the Orionid meteoric shower will form the principal 

 display. The moon will be full, however, at the time of the 

 maximum (about October 18th to "JOth), but the earl_y part of the 

 shower, on October r2th to 16th, may be well observed if clear 

 weather prevail?. 



■*- 



By John H. Cooke, f.l.s., f.g.s. 



The addition of a little ammonia to the water in which dia- 

 tomaceous materials are being washed facilitates the removal of 

 slimy, gelatinous products, cleanses the diatoms, and hastens 

 their settlement to the bottom of the vessel. 



To extract siliceous or.ganisms from rook fragments, heat the 

 rock to about one hundred degrees Fahrenheit, and then plunge 

 it into a boiling solution of soda sulphate. This salt takes 

 up water as it crystallizes, and the rock, therefore, readily 

 pulverizes under its influence. 



Balsam of tolu, from which the ciunamic and benzoic acids 

 have been removed by prolonged boiling in a large quantity of 

 water, is an admirable mountant for diatoms. It should be 

 dissolved in rectified benzine, filtered, dried, and finally dissolved 

 in alcohol or chloroform. Tlie refractive index of the balsam 

 thus prepared is 1'7'i when di-y. 



Methyl-green is an effective double stain for all vegetable 

 sections. When applied to fibres, whether of pure cellulose or 

 of lignin, it produces a deep green if the fibre has been mor- 

 danted before staining ; while a light green is produced when 

 the order of stain and mordant is reversed. Apply in a strong 

 aqueous solution. 



For the preparation of permanent mounts of living amaiboid 

 organisms, the following method, first suggested by Certes, will 

 be found to give satisfactory results. To thirty cubic centi- 

 metres of the water containing the living amoebae, add about 

 one cubic centimetre of osmic acid solution (one per cent.). 

 After settling for a few hours wash the deposit, concentrate, 

 stain, and mount in distilled water containing a trace of osmic 

 acid. 



To demonstrate in yeast cultures the formation of alcohol as 

 a result of the growth of the pliint in a sugar solution, Mr. A. 

 L. Treadwell suggests the following method as being less 

 troublesome than the ordinary qualitative tests, and much moi-e 

 satisfactory. To the yeast culture add a few drops of iodine 

 solution, and then enough KHO solution to destroy the colour 

 of the iodine. Iodoform will be produced and can be recognized 

 \>y its characteristic odour. 



The proper preservation of soft-bodied organisms is one of 

 the chief difficulties that the working micrcscopist has to con- 

 tend against. The number of preserving media is great, but 

 there are few of them that are at once as simple and effective 

 as that suggested by A. E. Ten-ill for preserving insects in 

 their natural forms and colours. The solution consists of two- 

 and-a-half pounds of common salt and four ounces of nitre 

 dissolved in a gallon of water and filtered. The specimens 

 should be prepared for permanent preservation in this solution 

 by being previou.sly immersed in a solution consisting of a 

 quart of the first solution and two ounces of arsenite of potash 

 in a gallon of water. 



To kill sponges extended, Mr. W. E. Melby proceeds thus : 

 The specimen is placed in a glass jar filled with water, and the 

 following solution is added drop by drop at intervals of one 

 minute : — Methyl alcohol, tea parts ; salt water, ninety parts ; 

 natrium chloride, six-tenths of a part. If the specimen does 

 not retract after forty-five minutes, pour some hot sublimate on 

 quickly. To preserve specimens for sections, put them in one 

 per cent, osmic acid for two minutes and then successively in 

 five, ten, twenty, thirty per cent, alcohol up to ninety per cent., 

 harden in absolute alcohol and imbed in paraffin, stain with 

 borax carmine and hfematoxylin. 



The distribution of aquatic life from season to season 

 throughout the various zones of the plankton in the larger 

 masses of water of the globe is an object of study which has 

 received considerable attention at the hands of investigators 

 during the last decade. The greatest difficulty that has been 

 experienced has been the need of an apparatus upon which the 

 operator can rely to work satisfactorily under all conditions and 

 at all times of the year. The nets that are usually used cannot 

 claim these advantages, inasmuch as they are always liable to 

 damage and loss when working on a rocky bottom, and during 

 the winter months, when the plankton yields its most in- 

 teresting i-esults they are inadmis.sible in northern latitudes 

 owing to floating ice. The accuracy of the results, too, leave 

 much to be desired, as with the net it is not possible to deter- 

 mine exactly the volume of organisms actually present in a 

 given quantity of water, nor is it practicable to determine the 

 various groups that are characteristic of the many vertical zones 

 or strata of water of which the plankton is constituted. 



For critical work, nets have had to be discarded, and in place 

 of them Dr. H. B. Ward has used, during his recent investiga- 

 tions on the Great Lakes, a light weight force pump which he 

 calls the "plankton'' pump, and which can be carried about and 

 operated by one person. The cylinder of the machine is eleven 

 inches long by three and a half inches diameter, and it has a 

 capacity of three hundred and forty-seven and a half cubic 

 inches per stroke. It is essentially an ordinary force pump, 

 save that it has very finely ground check valves, to which, it is 

 believed, the accuracy of the working of the apparatus is largely 

 due. The pump is connected with the w.ater by a hose one and 

 a half inches in diameter, the lower end of which is adjusted to 

 the various vertical zones of water by means of an attachment 

 to a floating block. Most gratifying results have attended the 

 use of this apparatus. It is possible to measure with great 

 accuracy the amount of water filtered. Collecting can be 

 carried on without any disturbance of the water, and water can 

 be drawn from any stratum, thus enabling the investigator to 

 examine in detail the vertical distribution of the plankton. 



Dr. H. A. Hagen has made careful records for the purpose of 

 determining the durability of the rubber stoppers which are 

 used in vials containing microscopic objects in alcohol. From 

 an examination of some seven thousand vials with rubber 

 stoppers, two-thirds of which had been in use for from ten to 

 twelve years, he comes to the conclusion that less than one in a 

 tliousand gives out every year after twelve years' use, and in 

 the first six years probably only one out of two thousand. 

 Stoppers of large size keep much longer than those of small 

 size. American rubber stoppers are all made of vulcanized 

 indiarubber, and have the dis,advantage of forming small crystals 

 of sulphur about the stopper, whicH become loosened and attach 

 themselves to the specimens. It is supposed that pure rubber 

 stoppers used for chemical ])urposes would not present this 

 disadvantage, which may be obviated, however, or very much 

 reduced, if the stoppers are washed or soaked in hot water for 

 an hour or two before being used. 



