40 



KNOV/LEDGE ♦ 



[June 16, 1882. 



the sun's rays is increased or diminished according to the 

 seasons. The effect of this obliquity on tlie mean tempera- 

 ture of tlie air will be seen by comparing the following 

 mean temperatures within the different latitudes which 

 cross England. We have taken the observations made in 

 1881 as illustrations. Between tlie parallels of latitude 

 50° and 51° N. there was no large town included, so that 

 the figures really represent the mean air temperature of 

 the South coast :— 



M»«n Air Mc»n Air 



Latusdo N. Tomporaturc. S('4siJo Temperature. 



Fahirnheit. Tow-ns. Fahrenheit. 



Between 50° and 51° 49° 1' South Coast 49° 1' 



51° „ 52° 48° 1' Barnstaple 50° 5' 



52° „ 53° 46° 9' Lowestoft 47° C 



53° „ 54° 46° 4' Llandudno 48° 6' 



„ 54° „ 55° 45° 4' Scarborough 47° 2' 



"We have selected the above sea-side health resorts as good 

 representatives of each of the interlatitudinal belts given 

 above for the sake of comparing their mean air tempera- 

 tures with those derived from the forty-three inland and 

 coast stations where the observations were made which 

 form the liasis of the above results. A glance at the above 

 figures will at once demonstrate how mucli higher the mean 

 temperature of the air is for cacli latitude along the coast 

 than the mean of England and Wales, which, of course, 

 includes the mean temperatures of both inland and coast 

 stations. 



Another fact connected with the obliquity of the sun's 

 rays according to latitude is tlie postponemcni of the time 

 at which the hottest and coldest periods of the days and 

 the sea.sons take place. 



In all latitudes the hour of greatest daily warmth follows 

 at certain intervals that of the greatest solar elevation, viz., 

 noon ; for instance, at Plymouth (about 50° 23' N.) the 

 warmest hour of the day in the sliade is at one p.m., or 

 rather a little after that hour ;* at York (about 53° 52' N.) 

 it is about two p.m. ; and at Leith + (a little south of 56° N.) 

 it is 2.40 p.m.; so that the hour of greatest heat takes 

 place nearly 1 hour and 40 minutes later in lat. 56" N. 

 than it does at 50° 23' N. We shall find in the sequel 

 that large masses of elevated land and the sea operate 

 powerfully in modifying the effect of latitude on the mean 

 temperature. This, to a certain extent, has already been 

 shown in the table above. 



To illustrate the postponement of the effect of summer 

 and winter on large masses of elevated matter we may 

 instance the experiments made at York Minster, and 

 recorded by John Phillips, F.R.S., in his charming and 

 interesting work on the rivers, mountains, and sea-coast of 

 Yorkshire. He tells us that a series of daily observations 

 were made and continued for three years within the inte- 

 rior of the cathedral, and showed that the hottest day is 

 about Jive u-eeks after the summer solstice, or a forlniijhl 

 after the hottest day in the open air ; and the coldest day 

 five jr>;eki after thf; winter solstice, or & forlniyhl after 

 the coldest day in the open air. 



We shall have to refer to the storage of heat by elevated 

 mas-ses, such as isolat*^!! hills, and liill ranges in the neigh- 

 bourhood of certain seaside health-resorts, and the effect, 

 in postponing sea-son.s, the giving up of this heat produces, 

 later on ; but a fact M-hich bears on this subject should be 

 recorded and rememl)ered. 



Mf«srs. Quetelet and Forbes made a series of experi- 

 ments in Scotland, France, Belgium, and Germany on the 

 postyKjnement of the effect of summer and winter below the 

 surface of the ground. It was found that the middle of 



SirVV. HarriB, "Rep. of Brit. Assoc., 1839." 

 ir D. Brewster in " Edin. Phil. Transactions." 



summer and winter, or the extremes of heat and cold occur : 

 — At the surface, in July and January ; 3 ft. deep in August 

 and February ; 12 ft. deep in October and April ; 24 ft. deep 

 in December and June, and at less than 100 ft. in July and 

 January of the following year. So that within 100 ft. 

 from the surface, the seasons are as much re\ersed as at 

 the antipodes. These facts relative to the postponement 

 of the hot and cold periods agree with the old doggerel 

 proverbs, "As the day lengthens the cold strengthens," 

 and " The days grow hotter as they grow shorter." We 

 shall refer to this subject again when discussing the causes, 

 of the local climates of the several health-resorts. In our 

 next we shall discuss the effect of latitude on the dailij, 

 rawjc of temperulurc. 



HOME CURES FOR POISONS. 



I^HE use of copper vessels for preparing food has led t» 

 many cases of poisoning, though, as a matter of fact, 

 if copper utensils are carefully cleaned, and food which 

 has been cooked in them is not allowed to stand in them 

 till cooled, they may be used safely enough. This, how- 

 ever, ought not to be left to the care of servants, who, 

 not taking scientific views of such matters, find it diflicult 

 to understand how the utensil which was clean when 

 food was put into it to be cooked, may bo (chemically)- 

 unclean when the food is taken out of it. To this 

 must be added that copper vessels, however clean, 

 are not fit utensils for cooking or keeping any 

 food of an acid nature. The practice of putting- 

 copper coins into pickles to give them a pretty 

 green colour used to be considered by some house- 

 keepers of former times a rather clever thing. This colour 

 was derived from the verdigris (or subacetate of copper), 

 formed by the combination of acetic acid and the oxide of 

 copper — and it is hardly necessary to say that verdigris is- 

 a poison ; but the green of the pickles was very pleasant to- 

 look at. Probably, now that copper coins are scarce, the 

 practice of adding copper in this cheerful manner, to poison 

 our pickles, is not .so common as it used to be. It should 

 be added that tinning the interior of co])pers is only a pro- 

 tection so long as the tinning remains entire. 



Arseniate of copper (Scheele's green, or mineral green), 

 is formed from the combination of arsenious acid with 

 oxide of copper. Sulphate of copper (l)lue vitriol, blue 

 copperas, or blue-stone) is made in largo quantities fop- 

 dyeing and colouring purposes. It is not very likely to be- 

 taken by accident, as it has a most unpleasant metallic taste. 



Sy.mptoms. 

 The symptoms of poisoning by any of the salts of copper 

 are vomiting, violent colic, convulsive movement of head,, 

 metallic taste in the mouth, pains in the thighs, h^g cramps, 

 laboured breathing, followed by lethargy. Jiut sometimes 

 lethargy and partial insensibility are among the first, 

 symptoms noted, the symptoms of irritation coming later.. 

 Yellowness of the skin, as in jaundice, is a characteristic 

 feature of poisoning by copper, at least so far as metallic 

 poisons are concerned. In some cases, slow poisoning by 

 copper occurs, where copper ves.sels, for instance, are used 

 daily with insufficieilt precautions. In these cases death 

 often follows; and it is then found, in poHl-morlnm examinai- 

 tion, that copper has accumulated in the liver. 



Home Remediks. 

 In cases of copper poisoning, the vomiting caused by the 

 poison sliould be encouraged by copious draughts of tepid 



