Dec. 23, 1886] 



NA TURE 



stone Gallery -! tr°' ^ 



Of the numerous experiments recorded in the paper, the follow- 

 ing series made at St. Paul's may be specially referred to, both as 

 illustrating the quantitative accuracy of the process, as well as 

 showing how it may be employed in ascertaining the distribution 

 of micro-organisms in the atmosphere : — 



Number of micro- 

 November 19, i386 organisms found in 



10 litres of air 



St. Paul's Churchyard 47 



' " 40 



35 

 No. I 



Golden Gallery ^ No. 2 11 



( No. 3 11 



The following are the principal advantages which the author 

 claims for the " flask-method " : — 



(i) The process possesses all the well-known advantages 

 attaching to the use of a solid cultivating medium. 



(2) The results, as tested by the comparison of parallel experi- 

 ments, can lay claim to a high degree of quantitative accuracy. 



(3) The results, as tested by control experiments, are not 

 appreciably aflected by aerial currents, which prove such a dis- 

 turbing factor in the results obtained by some other methods. 



(4) The collection of an adequate sample of air occupies a 

 very short space of time, so that a much larger volume of air 

 can be conveniently operated upon than is the case with Hesse's 

 method. Thus, whilst the aspiration of 10 litres of air through 

 Hesse's apparatus takes about three-quarters of an hour, by the 

 new method about 48 litres can be drawn through the tube in 

 the same time ; whilst a better plan is to take two tubes and 

 alternately draw a definite volume of air through each, as by 

 this means duplicate results are obtained. 



(5) As the whole plug upon which the organisms from a given 

 volume of air are deposited is submitted to cultivation without 

 subdivision, no error is introduced through the multiplication of 

 results obtained from aliquot parts, and all the great difficulties 

 attending equal subdivision are avoided. 



(6) The risk of aerial contamination gin the process oi flask- 

 culthatioH is practically nil. 



(7) The apparatus required being very simple and highly 

 portable, the method is admirably adapted for the performance 

 of experiments at a distance from home, and in the absence of 

 special laboratory appliances. 



" Further Experiments on the Distribution of Micro-organisms 

 in Air (by Hesse's method)." By Percy F. Frankland, Ph.D., 

 B.Sc, F.C.S., F.I.C., and T. G. Hart, A.R.S.M. 



The authors record a number of experiments, made with 

 Hesse's apparatus, on the prevalence of micro-organisms in the 

 atmosphere. The results are intended to form a supplement to 

 those already obtained by one of the authors, and published in 

 the last number of the Society's Proceedings. The greater num- 

 ber of the experiments have been performed on the roof of the 

 Science Schools, South Kensington, the air of which has now 

 been under observation at frequent intervals during the present 

 year. The authors point out the variations, according to season, 

 which have taken place in the number of micro-organisms present 

 in the air collected in the above place. The average results 

 obtained were as follows : — 



Average number of micro-organisms 

 found in 10 litres of air by 



January ... 

 March 

 May 

 June 



July ... 

 August ... 

 September 

 October ... 



He: 



ethod 



^ Experiments are also recorded showing the enormous increase 

 in the number of micro-organisms present in the air of rooms 

 consequent on crowding. In illustration of this point the 

 authors cite a series of experiments made in the library of the 

 Royal Society during the evening of the conversazione in June 

 last," when the following results were obtained : — 



Number of micro- 

 organisms found in 

 10 litres of air 

 326 



Royal Society's Library 

 June 9, I 

 June 10, I 



9.20 p.m. 



lo.S „ 

 10.15 ^•'"• 



432 

 130 



In addition to determining the number of organisms present in a 

 given volume of air, the authors have also, in each case, roughly 

 estimated the number falling on a given horizontal surface by 

 exposing dishes filled with nutrient gelatine and of known super- 

 ficial area, as in the experiments previously published. 



Society of Antiquaries, December 9. — Dr. John Evans, 

 President, in the chair. — Mr. J. Allen Brown, F.G.S., F.R.G.S., 

 read a paper on his discovery of a Palaeolithic workshop floor of 

 the Drift period near Ealing. He pointed out that the discovery 

 of this PaIa;olithic working site fully confirmed his previous 

 observations of the higher river-drift deposits in North-West 

 Middlesex, i.e. that such old floors or former land surfaces are 

 often discernible therein, and that such habitable spots have 

 been preserved in different parts of the Thames Valley, though 

 they have frequently been disturbed, removed, and re-deposited 

 in other places by the changing course and curves of the wider 

 river of the p.ast, and by floods and other conditions of the severer 

 climate which then prevailed. This Paleolithic workshop floor, 

 which is about 100 feet above the present bed of the Thames, 

 and about two miles distant from it, is situated near the 

 junction between the Creffield Road and Mason's Green Road, 

 Acton ; the floor is here about 6 feet from the surface, with a 

 steeper slope to the river than the present surface ; it is covered 

 to this extent with sand, brick earth, and trail deposits. At this 

 site, on an area of about 40 feet square, were found nearly 600 

 unabraded worked flints, including long spear or javelin heads 

 from 5 to 6 inches long, neatly trimmed to a point, and of the 

 same form as those of obsidian, &c., now employed by the 

 natives of New Caledonia, the Admiralty Islands, and Australia, 

 for insertion into the shafts of their spears, to which they were 

 fixed by lashings, &c. There were also shorter ones, not only 

 wrought along the sides to the point where the flake required 

 trimming, but also neatly chipped at the butts into rough rudi- 

 mentary tangs. Such spear-heads have not only been described 

 by Messrs. Lartet and Christy from the cave of Le Moustier, in 

 the Dordogne, but have been met with in the alluvial deposits 

 of the Somme at Abbeville, the Seine, and other French rivers, 

 as well as by Dr. J. Evans, from Mildenhall, &c. Roughly 

 wrought hatchets, axes, or choppers formed from flakes chipped 

 on one or both faces to a cutting edge were also found 

 rather abundantly on the floor. They are probably some 

 of the earliest rude celt forms, and have been found also 

 in other gravel deposits of the district. At the Creffield Road 

 site they were discovered both finished and unfinished, and 

 correspond with similar tools described by Dr. Evans from the 

 high-level deposits at High Lodge, Mildenhall, Santon Down- 

 ham, and Fisherton, near Salisbury, &c., as well as in the high- 

 level Quaternary drift at Sauvigny (Loire) descrilied by Dr. H. 

 Jacquinot, and in the deposits of Le Moustier (Dordogne), &c. 

 Some of the specimens exh;l>ited were worked on both faces and 

 pointed, thus approaching the Saint Acheul types, which _M. 

 G. de Mortillet considers as belonging to the earliest dnit series, 

 that of the Chelleen epoch ; they have also been described from 

 other places in North-West Middlesex, as well as by Prof. Boyd- 

 Dawkins from Wookey Hole, and by Dr. Evans from Bidden- 

 ham, Bedford, Thetford, &c. Among the most interesting 

 implements exhibited were borers, awls, or drills, some being 

 large enough for boring wood ; while others were sufficiently 

 small for piercing bone needles, and also flints with neatly 

 chipped symmetrical depressions, which it is believed were used 

 as shaft-smoothers, or spokeshaves, like those lately exhibited in 

 Mr. Dunn's collection of Bushman and Hottentot stone imple- 

 plements at the Colonial and Indian Exhibition. Lar^'e numbers 

 of knives formed from flakes, often neatly worked on the edge 

 with fine secondary work, and also saws chipped with a dis- 

 tinctly serrated edge, were exhibited from this site, with other 

 tools apparently intended to be used as chisels, &c. L rge 

 numbers of waste flakes, as well as blocks of flint which had 

 been worked upon, were also found at this spot ; and in Ealing, 

 about two miles distant, in a deposit of about the same age, a 

 large boulder of metamorphic rock, concave on both faces 

 and roughened and scored in the hollows from use, was 

 met with ; it is ^\ inches long : and a quartzite boulder 

 which fits the hollows was found near it, in fine gravel. 

 They are the first pounding-stones discovered in the drift 

 deposits. The author — after describing the v.irious typical 

 forms of the flint implements from the river- drift deposits of 

 Ealing, Acton, Hanwell, Dawley, &c., in his large collection, 

 and their respective ages, as educed from the position or level 

 at which they have been found, as well as their condition. 



