AX IJIPROVED BURETTE HOLDER.*
BY A. A. BRENEMAX. The burette holder shown i n the cut is a modified form of one t h a t I have seen, but of which I d o n o t know the origiii. The original features of the present oiie are t h e use of a spiral spring much longer than in tlic original holder, imbedded in ii wooden block which can be clamped a t will to the upright part of any laboratory shelf, thus disliensing wvith a stand and leaving the table clear, while not interfering w i t h the use of the shelf, and of the combination or' two Iioltlers in one, as shown in the cnt.
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AK I Y P R O T ' E D B U R E T T E H O L D E R .
'I'lie springs C, J, mliicli are 10-12 em. long, are made of hard braes wire of about 8 nim. diameter, coiled as closely tis possible. O l i o end 31, terminating iii a closed 1001) is sunk inti.) il deep longit~udinal hole L, parallel with the :&xis of the block. T h e loop is held firmly by a screw wliich passcs through it from tlie ontside. The spring, when not extended. reaclies within 1 c.m. of tlie opeiiiiig. T h e stirrup I. is connected with it b- its middle loop and is then held so as t o support eve11 :I vel,? small tube within its rings hy drawiiip tlie tube against blie j a w of the block. The grooves ;ire faced with cork, first glued in place and theii sliaped with a round file. These are afterwards w l i rubbed with niclted paraffine as is also the entire surface of the wooden block, t l i u s affording protection against acid or caustic: solntions. Tlie wire portions are lacquered, or better, plated wit11 platinum. The rings of tlie stirrup are bent to a n arc of about '3rX)c, The entire block is 2 3 em. long, 10 em. wide, and 2 em. thick. T h e beveled portion is 15 x 10 s 2.5 e m . Tlie large double hook €3, is an indispensable part uf the holder. Introduced a t the side of the stirrup, opposite tlie opening of the rings, it is used to draw tlie stirrup forward for the removal or insertion of a burette. Tlie readiness with which burettes can be moved LIP or down, or rotated, with a single movement and with one hand, is a marked advantage of this holder. The superiority of wire over silk or catgut, sometimes used in burette stands, will be apparent, and the cleariiess of Tiew afforded, as compared with t h e use of t h e usual burette clamp, is :mother advantage. T h e holder is held in place against tlie upright part of the shelf by :t common iron clanip F, readily obtairied of any Iiardware dealer. h small block of mood G, 3 x 3 ~ 1em., with a hole running partly through it, serves as a sockat for the end of tile iicrew to prevent defacing of the shelf t o which the holder is attachkd.
