CHE.\TIS'I'ICY AX11 1SDUS'l'RY
ARTIFICIAL DISSIPATION OF FOG
JIiitty ingenious, but unpractiail, suggcstions liavc Iiccn n t difl'ercnt tiincs itdvnnccd to sccurc tlic locnl clcnritig of fog, ~~nrticulnrly at ncrotlroincs. 111 at1 articlc which hiis lust bccn ~~ublislicd by tlic Jnstitutc of Physics i i i its Jouritnl of Scientific Instrotnctits, l'rof. D;t\*itl h u n t , l'rorcssor of Nctcorology a t tlic Iiitperial C'ollcgc of Scicticc nitd Tccliuology, Loatloit, gives ii criticiil irniilysis of possililc nictliotls itritl iirriws :it soitic iiitcrcstitig coiiclusions.
Fogs, Itc poiitts out,, itrc of two ntaiii tylics-" riidiatioii fogs," producctl by tlie coolitig of tltc cnrtli's surfnet: oil ii cleitr night, iind fogs duc to tlic itiflow of w t r i i i dnitip air over it cold surfncc. Tlic first type i3 ouly produccd i t i the rtbscttcc of any itpl)rccirrblc riir tnovcnicitL, ntiil no pructicnl solution to the probhn ahicli they pcsctit hns yct bccn found. Fogs of tlic sccotid type liilve, lio~vcvcr, it nicrtsurttblc spcctl of motion, niitl iii orcler to prorlucc a patch of clcnr air, it is sollicicnt to ripply lociil treitttitcnt ciloiig n line oti tlic wiiidwtrd side.
d viiricty of prilcticiil cotisidcrutio~is litnit tlic inctliocls which titight be uscd. Tlic two inost importrint iirc that m y iiiethoil, t o bc clYectivc, niust bc cn1)d.de of acting quickly tltrougltout il height of up to iil~out 100 tiictrcs ; iiiid t h n t whntcvcr cquiptnent is itccessary iuust not itself constitute nil obstaclc to air trdlic. For csniiiplc, ltowevcr cn'ectivc thcorcticnlly a ticrics of calcium chloridc sprays iniglit IN in ubsorbing moistitre from tlic nir, it is u fiititl objection tltitt the spriiying p i p s \vould have to bc plncctl iit or iicnr tlic ulq~er littiit OC tltc fog.