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contrived by him for excluding the action of atmospheric air during the process of filtration. By means of it, this process may be conducted either in a confined portion of air, in vacuo, or in any gas.

“ It is frequently important in chemical analysis to conduct the process of filtration either in vacuo or in a neutral gas, and especially in an atmosphere free from carbonic acid. In order to overcome certain difficulties, I have been led to contrive an apparatus for this purpose, which I believe to be superior to all others now in use, both on account of its simplicity and its cheapness. The complete apparatus is represented in Fig. 1, and some of its parts enlarged appear in Fig. 2. It consists of a wide-mouthed glass bottle, into the neck of

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which is ground with emory a funnel (a, Fig. 2), having a short but large spout. This funnel is made sufficiently thick to resist the atmospheric pressure, and its rim is ground so that it may be closed air-tight by a glass plate, or by a brass plate, connecting with an airpump. Within this outer funnel the common filtering-funnel is placed, resting loosely against its side so as to allow a free passage of air. In order to wash the precipitate, a glass plate having a hole an inch and a half in diameter drilled through its centre (d, Fig. 2) is substituted for the covering-plate. Through this passes the tube of the washing-bottle (f, Fig. 2). The washing-bottle is made in the ordinary way, except that it is fitted with a cork, which projects about an inch above the neck. The upper end of the cork fits the neck of a glass plate ground on the under side, made as is represented at e, Fig. 2. This plate is about three inches in diameter, and when resting upon the plate d, as is represented in Fig. 1, covers the hole completely, and permits sufficient lateral motion to bring the stream of water on different parts of the precipitate.

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“ Numerous processes in (which this apparatus may be applied will suggest themselves to any chemist. I will only mention one in which I have found it very useful. In the ordinary process of separating alumina and sesquioxide of iron from the alkaline earths, the sesquibases are precipitated by caustic ammonia, which does not, as is well known, precipitate the alkaline earths when perfectly caustic. Since, however, the best liquid ammonia contains carbonic acid, and as, during the precipitation and subsequent filtration, carbonic acid is absorbed from the air, it invariably happens that small amounts of the alkaline earths are precipitated as carbonates. It becomes, therefore, necessary to redissolve the precipitate, and repeat the process in order to obtain a complete separation. This repetition, I think, may be avoided by using ammonia gas made caustic by lime, and conducting the filtration in the apparatus just described. The substitution of ammonia gas for liquid ammonia in this process has been made by many

chemists. I use for precipitating with caustic ammonia gas the little apparatus represented in Fig. 3. Strong liquid ammonia is placed in the flask, where it is gently heated, and the resulting gas passed through a chloride of calcium tube into the solution. To the end

of the bent tube I attach, by means of a caoutchouc connector, a short tube which dips into the fluid. This, when the precipitation is completed, can readily be disconnected, and any adhering precipitate easily removed. The fluid with the precipi. tate I now throw upon the filter arranged in the apparatus above described. As the process of filtering and the subsequent washing is conducted in a very confined space, which can easily be entirely deprived of carbonic acid, no precipitation of the alkaline earths is possible, so that they are completely separated from alumina and sesquioxide of iron at the first precipitation.

“I use two sizes of the filtering apparatus, which differ from each other, however, only in the size of the bottle. In both, the diameter

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of the outer funnel is about five inches, but in one size the bottle has the capacity of a pint and in the other of a quart. I employ the larger size only when a prolonged washing of the precipitate is necessary. The cost of the apparatus complete is only two dollars, the price of an ordinary filtering-stand with iron rings.”

Professor Gray presented a communication entitled, “Notices of New Species of Mosses from the Pacific Islands,” by William S. Sullivant.

“ The Mosses here noticed are a part of the collections made by the United States Exploring Expedition under the command of Captain Charles Wilkes ; and are presented in this form for the purpose of securing to the Expedition the priority of their discovery. Similar notices of new Mosses and Hepaticæ from Tierra del Fuego and Oregon, belonging to the same collections, have already appeared in the second volume of Hooker's Journal of Botany (1850).

“1. HYPNUM APERTUM (n. sp.): monoicum ; caule prostrato elongato arcte repente pinnatim ramoso ; ramis dissitis inæqualibus complanatis ; foliis laxissime bifariam imbricatis suboblique orbiculari. ovatis acuminulatis concaviusculis ecostatis firmiusculis subscariosis pellucidis estriatis integerrimis nitidis minute elliptico-areolatis ; capsula suburceolata horizontali pendulave annulata ; operculo hemisphæ. rico-conico ; pedicello flexuoso-erecto lævi. – Hab. On the ground, Tahiti, Society Islands.

“2. HYPNUM MOLLUSCOIDES (n. sp.): pusillum, dioicum ; cæspite deplanato intricato mollissimo lutescente; caule fasciculatim diviso, divisionibus densissime plumæformi-pinnatis ; foliis e basi lata lanceolato-attenuatis falcatis secundis vix serrulatis costellis binis brevissimis indistinctis minute lineari-areolatis cellulis basilaribus laxioribus majoribus ; perichætialibus stricto-convolutaceis apice longe attenuatis patentibus ; capsula minuta ovali-urceolata horizontali vel pendula ; dent peristomialibus lanceolato-subulatis dense trabeculatis, ciliis carinato-stereodontibus, ciliolis singulis binisve validis granulosis sæpe rimosis ; annulo ægre solubili; operculo hemisphærico-conico recte rostellato ; pedicello longiusculo gracillimo. — Hab. Tahiti, Society Islands.

“ 3. HYPNUM WILKESIANUM (n. sp.): dioicum, majusculum, sordide rufescens; cæspitibus extensis laxis ; caulibus prostratis rigidiusculis VOL. III.

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paucirameis vel dissite subpinnatis, ramulis longiusculis attenuatis teretibus vel subcompressis basi fructiferis ; foliis ovato-lanceolatis concavis patenti-divergentibus incurviusculis ruguloso-striatis basi lata saccato.plicatis, margine toto ambitu serrulatis inferneque recurvis, costa valida ad apicem fere attingente, dense areolatis, cellulis minutissimis oblongis ; perichætialibus exterioribus squarrulosis interioribus filiformi-elongatis erecto-flexuosis apice serratis ; capsula cylindraceo. oblonga erecta subæquali annulata basi subattenuata ; operculo longe erecto-aciculari-rostrato ; pedicello flexuoso longissimo; peristomii dentibus lineari-attenuatis strictiusculis dense trabeculatis, ciliis e membrana eciliolata tenuibus carinatis ; columella emergente; sporis majusculis ; archegoniis 40 - 50; antheridiis 35 – 40; paraphysibus floris utriusque copiosissimis. - Hab. Hawaii, Sandwich Islands.

“4. HYPNUM PICKERINGII (n. sp.): monoicum, pusillum, plumulosum ; cæspite compacto; caulibus inferne sordide rufescentibus superne aurescentibus nitidulis vage ramosis; ramis erectiusculis apice subuncinatis dense subcompresse foliosis ; foliis oblongo-lanceolatis concavis filiformi-attenuatis basi patentibus dehinc erecto-incurvis apice subtubuloso serrulato patentiusculo interdum subsecundis ecostatis scariosis, cellulis densissimis valde elongatis transversim striato-granu. losis plus minus minutissime papillulosis, alaribus utrinque binis ternisve subquadratis amplissimis vesiculæformibus hyalinis flavidulis ; perichætialibus oblongo-convolutaceis subito serrato-acuminatis ; pedicello longiusculo tenui debili superne tuberculoso-scaberrimo inferne lævi ; capsula minuta ovali-urceolata subpendula ; peristomii dentibus linea axili lata pellucida notatis dense articulatis intus valde prominenter lamellosis ; ciliis e lata membrana carinatis foraminulosis capillariattenuatis ciliolis singulis interpositis ; operculo longissime aciculari. rostrato ; calyptræ junioris cellulis spiraliter dispositis. – Hab. Mountains behind Honolulu, Oahu, Sandwich Islands.

“5. HYPNUM ARCUATUM (n. sp.): monoicum, plumulosum, delicatulum ; caule prostrato rectangulariter parce diviso, divisionibus breviusculis dense pinnatis, ramulis compressiusculis ; foliis lanceolatis acuminatis serrulatis ecostatis patenti-divergentibus incurviusculis laxe positis distiche directis minute lineari-areolatis; capsulis inæquilateralibus annulatis e pedicelli longissimi arcu latissimo apiciali pendulis ; operculo hemisphærico-conico; flore masculo gemmiformi cauligeno, antheridiis 8 - 10 paraphysatis. – Hab. East Maui, Sandwich Islands.

“6. HYPNUM MUNDULUM (n. sp.): monoicum, parvulum, delicatulum, pallide lutescenti-viride, laxe implexum ; caule repente parce diviso pinnatim confertius ramuloso; foliis patentibus laxissime disticheque dispositis e basi constricta subauriculata lanceolatis longe acuminatis concaviusculis ecostatis, marginibus erectis superne lenissime serrulatis tenuissime lineari-areolatis, cellulis basilaribus amplissimis oblongis vesiculæformibus pellucidis ; pedicellis aggregatis tenuibus longiusculis lævibus ; capsula gibboso-brevi-oblonga ; operculo conico acuminulato; perichætialibus oblongo-convolutaceis ex apice rotundata erosodentata subito in acumen longissimum filiforme flexuosum varie directum eductis ; antheridiis 12 – 15, abunde paraphysatis ; fol. perigon. filiformi-acuminatis. — Hab. District of Puna, Hawaii, Sandwich Islands.

7. HYPNUM ? SPECIOSISSIMUM (n. sp.): elatum, filicoideum, aures. cente-spadiceum ; caule (plantis masculis tantum visis) primario repente radiciformi robusto radiculis atropurpureis densissime vestito, stipites fuscos erectos firmos minute squamæformi-foliosos (veluti nudos) apice in frondem planam ovato-lanceolatam superne pinnatim inferne bipinnatim ramosam ramificatos emittente; ramis superioribus patentibus strictis hystricose-foliosis, inferioribus patentioribus rectangulariter ramulosis, ramulis breviusculis subgeniculato-flexis ; foliis axis centralis majusculis dissitis strictis bifariis elongato-triangularilanceolatis longe acuminatis subplanis, rameis ramulinisque multo minoribus confertis erecto-patentibus e basi elongato-elliptica longissime lineari-eductis, omnibus superne argute serratis margine plus minus indistincte incrassato-limbatis costa dorso versus apicem dentata valida percurrente cuspidatis; areolatione densissima e cellulis minutis linearibus prosenchymaticis maxime pachydermibus composita ; perigoniis numerosis valde conspicuis elongato-ellipsoideis acuminatis substipitatis axillaribus in ramorum axisque superiorum longitudine utrinque seriatim positis ; foliis perigon. inferioribus minutis ovato-acutis, superioribus convoluto-lanceolatis filiformi-acuminatis usque ad apicem subdentatam costatis, interioribus late ellipticis convolutis breviter obtuse apiculatis mediotinus costatis ; antheridiis 3-5 majusculis elongatis pedicellatis paraphysatis. — Hab. Feejee Islands.

“8. HYPNUM TUTUILUM (n. sp.) : monoicum ; caule prostrato ex. tense arcteque repente bis terve diviso, divisionibus densissime pinna

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