is very scldom that a clicmical compound ciiii rciiisiii :I wcll-known tlcnizcn in tlic .scientific Iriborntory for nearly a Iiiindred yciirs witliout iinyonc siispccting thnt it may havc iinportant industrial applications. Pct this hrtppcns to bc the crisc with solid CO,, which was discovcrccl ninety-ciglit yctirs ngo by Tliiloricr and only proclriccd commcrci:illy for tlic first time in 1921. Thc frict is thc morc rcninrkiiblc, bcciiusc the production of solid CO, is by no meiins m r y difficult as industrinl proccsscs go, iiiid its ripplication as n rcfrigcrnnt is obvious cnoiigli, nlthough tlic mcthods tlmt must IIC ndoptcd if siicccss is to be ncliicred arc sonictimcs a little i n-olvctl.
I h r i n g tltc iiitcrviil of tiinc bct~rcen tlic discovcry of solid CO,, ninety-ciglit ycars tigo, rind its comiiicrcinl production in 1'324, only two people, so far ns I know, giiw w r y serious tliought to its commcrcial possi-bi1itic.s. 'l'hcsc two pcoplc wcrc Dr. Elwortliy and Xr. Slirtc. h i t tluring this pcriotl of its conimcrcinl obscurity one crinnot siiy thrit solid COz wis born to sublime unseen iind wiistc its coltl~icss on thc laboratory air, for csl)crimcntcrs turned to it thitnkfully iis a mcitns of obtuiuing low tcmpcraturcs, nnd lccturcrs found it inrriluiiblc for tcncliiiig students of tlic phasc rule tlic grii rid basic truth that siibstanccs citn, and some hiiljstiinccs do, liiivc boiling points colder tliiin their frccziiig points.
Both Elworthy iind Slatc hoircvcr, thouglit solid CO, hnd couimcrciul possibilities. Elworthy was a doctor in tlic Jjritisli Army JIcdicnl Corps stiitioncd in Intlia, and onc of tlic ninny troubles in liis lifc was the difficulty of preparing good whisky and soda, particu-Iiirlp while on the mow. This tlifliculty tirose from tlic weight of the licnvy cyliridcrs used to contain tlic liquid cnrbon tliosidc for ircrntiiig tlic sodit wiitcr. Elworthy thcrciipon conccivcd tlic itlcii of solidifying his CO, and cnrrying round only about tlic nct weight of this cssentiiil constitucut of soda w t c r . Ire wits so plcnscd with this itlcii 1 lint hc pntciitctl it nnd now, thirty-fivc yerirs Iiitcr, his itlcn is bcing csploitcd commcrcinlly.
Slirtc, on tlic otlicr hitnd, wiis imprcsscd with tlic possibilities of solid CO, iis n rcfrigcrrint, nntl it \vns tliic to liiv cnthnsiiisin tlint tlic first pliint for tlic mriiiufticture of solid ciirbon diosidc irns erected in Jlontrcnl in 1924. Slate thouglit tliiit solid CO, would ciisily rcplacc icc ns a refrigerant in ridway ciirs, but his cspcrimcnts in this dircction WCTC not wry succcssful. 110 fiiiiilly tircd of solid CO,, went to Ciilifornin, iind applicd his invcntivc tillcuts to tlic construction of nirships. Thc solid CO, plnut that he Iind llclpcd to create rcmnincd, lio\vcvcr, and bccnnic tlic focus of ti liar industry. Aftcr vnrioiis unsiiccessfiil trials, solid cnrboii diosiilc fount1 its first ficld of usefulness in t Iic ice-creiim industry. Undcr tlic iiiimc of " Dry Ice " tlic first siilc took plncc to Schru(ft's Stores, Xcw York, i n 1!)25. 'rhc dry ice wns uscd by Scltrirlft's its a mcrins of coiintcrircting tho cllccts of tlic Ncw York suinnicr on tho icc crciiiit i n siniill pnckcts tnlccii liomc by ciistonicrs. * I h t l Iioforu it joint, tlicwtirig of tlw 1CditibiirgIi Scotion8 of t Iiu Sooiuty of Cliuiiiiciil liiiluntry IIIIII Tliu LiisLit utu of CIIVIIIitdry, 011 Mir. 23, 111:I:l.