. 



TERRESTRIAL TEMPERATURE. 



in the same latitude. Inland places experience a much greater degree 

 both of hot and cold than place* on the coart, and the difference 

 between thote degree* of heat and of cold increases with the distance 

 of the pbce from the M*. ThU phenomenon has been varioufily 

 explained. The explanation is now pretty clear, since it hu been 

 proved by obmration that the temperature of the air over the tea in 

 lea* subject to change* than, or rather doe* not undergo mich great 

 change* a*, that of the air which is over the land. But a* the tempe- 

 rature of countries situated between the tropics i* not subject to so 

 great change* a* that of countries in the temperate cone, and these 

 again are leas affected by them than the frigid cone, so it is found to 

 be the case on the se also. Beginning with the smallest natural 

 division of time, the day, it is found that between the tropics the 

 difference of temperature within 24 hours seldom exceeds 2 degrees 

 of Fahrenheit, and rarely amounts to more than 3 degrees. The 

 following table, from Heyen's ' Reise urn die Welt,' shows the changes 

 of temperature on the sea during 24 hours between the tropics : 



Ik. 



1 



: 



I 



' 

 I 

 7 







USO, October JS ; lat. M' 17' N., long. S6' S7' TV. 



800 

 80-06 

 80'0 

 7988 

 79-70 

 79-70 

 79-70 



9k. 

 10 

 11 

 11 



1 



I 



3 



4 



80-96' 



80-96 



80-96 



80-96 



81-U 



81-50 



81-96 



81-68 



5k. 



9 

 10 

 11 

 12 



81-14' 

 81-14 

 81-14 



80-96 

 80-78 

 80-96 

 80-34 

 80-24 



The difference between the highest and lowest temperature is only 

 2"J$. The mean temperature of the day is 80-65, which is only 0'95 

 above the lowest and 1-31 below the highest temperature. It must, 

 however, be remembered, that during the day to which these observa- 

 tions refer, the vessel on which they were made advanced through 

 nearly 14 degrees of latitude, which of course must have had some 

 effect on the temperature. 



There is a greater difference in the daily temperature of the sea 

 within the temperate zone : though when compared with the changes 

 which occur in any place situated in the same zone, but not immediately 

 on the shores of the sea, it will be found considerably less than in the 

 latter. The following table from Berghaus, of the changes on the sea, 

 may be compared with the changes in the temperature of London in 

 the middle of March : 



March 16; lat. 31 0' N., long. 64" 11' W. 



Ik. 



1 

 3 

 4 

 I 

 



7 

 8 



43-7- 



43-7 



43-7 



43-7 



44-6 



44-6 



44-G 



44- 



9k. 

 10 

 1) 

 12 



1 

 2 

 3 

 4 



446' 

 41-6 

 44-6 

 44-6 

 46-4 

 45-5 

 44-6 

 4J-7 



51-. 



9 

 10 

 11 

 12 



43-7 



42-8 



41-0 



41-0 



41-0 



41-9 



41-9 



42-8 



The difference between the maximum and minimum of the daily 

 temperature in this table amounts to 64*, and the mean temperature 

 of the day is 437. The maximum is 27 above the mean tempe- 

 rature, and the minimum is 27* below it. 



We come to the same conclusion that the temperature of the air 

 over the sea is subject to In* considerable changes than that which 

 surrounds the land, when we compare the change* that occur during 

 the seasons. Looking at the difference of temperature between the 

 hottest and coldest season in Berghaus s tables, we find that this differ- 

 ence is much greater, and at the same time more irregular, in the 

 northern than in the southern hemisphere. But this seems to be due, 

 in a great measure, to the influence of the Arctic current and to the 

 difference between the winter and summer temperature, owing to 

 the pretence of vast masse* of ice, which during winter extend as far 

 as 40' N. lat. ; between 5.V and 25 the increase of the mean 

 temperature of the spring is tolerably regular, rising from 44 to 6 for 

 every 6 degrees of latitude. The other irregularities ore evidently 

 produced by a greater increase of the heat in summer. The mean 

 temperature of the summer increases pretty regularly between 55* and 

 45' by from 2 to 4 degree* for every 6 degrees of latitude. But 

 between 45* and 40" it rue* suddenly to more than 6 degrees. This 

 sudden rise is, no doubt, produced by the warm vapours arising from 

 the Gulf-stream [ATLANTIC OCEAN, in OEOO. Dry.], which in these ports 

 runs acroas the Atlantic. Another rise of more than 6 degree* occurs 

 between 40* and 86 N. lat The air of the Sahara, when railed to the 

 highest degree of heat by the continuance of the sun near the northern 

 tropic, teem* to affect the mean temperature of the summer between 

 40' and IS*, and to raise it nearly to the mean temperature of that 

 Mason under the equator. The effect of this heated air ha* been 

 distinctly traced for on immense distance, we may, however, suppose 

 that it cease* near Cape Verde ; but the effects of another phenomenon 

 begin to operate. The region of calms [CALMS] frequently extends in 

 summer to 12* and 13* N. lat Of these three agents, the heated air 

 of the Sahara seems to have the greatest effect in raising the mimmcr 

 temperature of the Atlantic. Again, the fact that most of the isother- 

 mal lines run in a north-eastward direction from the western side of 

 the Atlantic toward* the eastern, and then bend downwards toward* 



the couth, indicates, as Maury remark*, the presence along the African 

 shore* in the North Atlantic of a Urge volume of cooler waters, the 

 current of the Gulf stream. 



\\ li.-n two elements, such a* air and water, approach each other, 

 there can be no great difference hi their temperature. Still there mu*t 

 be some difference, as the air is the better conductor of heat, and the 

 water, as a more dense body, is capable of retaining it for a greater 

 length of time. Many observations have been made for the purpose 

 of establishing this difference more precisely. It has been found that 

 the temperature of both is subject to regular changes during the day, 

 but that the air attains its highest temperature about two o'clock, 

 whilst the sea attains its highest temperature in some parts at three 

 o'clock, in others not before four o'clock. Further, it appears that the 

 temperature of the air is greater shortly before and after noon, and 

 that of the sea about midnight ; but in the morning and evening the 

 two elements have nearly the same temperature. On the land, again, 

 the coldest and hottest months are February and August, but on the 

 sea the vast amount of observations collected by Maury (' Physical 

 Oeog. and Meteorology of the Sea,' ch. xvii., ed. 1860), show distinctly 

 that the extremes occur in March and September. It has further been 

 found, that " at sea the climatic conditions of the land are reversed, 

 for the coldest side of the ocean is next the warmest side of the con- 

 tinent, and vice vertd " (Maury), conditions, however, which a little 

 reflection will render readily comprehensible. When these slight 

 changes ore excluded, it is found that the difference of temperature in 

 both elements is inconsiderable, but differs in different latitudes. 



The great preponderance of water in the southern hemisphere Li.-oa 

 Dove has pointed out, the prime cause of the southern hemisphere 

 being a region of warm winters and cool summers, while the northern 

 ia characterised by cool winters and hot summers ; on increasing quan- 

 tity of the sun's heat becoming latent, as, in passing from north decli- 

 nation and entering the southern signs, it is employed in evaporating 

 on increasing quantity of aqueous vapour. And, as he observes, " the 

 mild winter of the southern hemisphere, plus the contemporaneous 

 hot summer of the northern, necessarily gives a higher sum of tempe- 

 rature than the cool summer of the southern plus the cold winter of 

 the northern hemisphere." These relations, he suggests, appear to 

 furnish, in the periodical conversion of the aqueous vapour into a 

 liquid form, the motive power in the machinery of the general atmos- 

 phere of the earth. " The unequal distribution of land and sea in 

 the northern and southern hemispheres appears to supply on effectual 

 provision, from whence it necessarily follows that the aqueous vapour, 

 which from the autumnal to the vernal equinox is developed to an 

 immense extent over the southern hemisphere, returns to the earth in 

 the other half of the year in the form of rain or snow. And thus the 

 wonderful march of the most powerful steam-engine with which we are 

 acquainted, the atmosphere, appears to be permanently regulated. . . . 

 It is probable that the northern hemisphere may be regarded, com- 

 paratively speaking and to a considerable degree, as the condenser in 

 this great steam-engine, and the southern hemisphere as its water- 

 reservoir; that the quantity of rain which falls in the northern 

 hemisphere is therefore considerably greater than that which falls in 

 the southern hemisphere ; and that one reason of the higher tempe- 

 rature of the northern hemisphere is, that the large quantity of heat 

 which becomes latent in the southern hemisphere in the formation of 

 aqueous vapour is set free in the northern in great falls of rain and 

 snow." (' Essay on Distribution of Heat,' p. 26, Eng. translation.) 



TKRKIER, from the French word terrier, a land-book, a register or 

 survey of lands. Those best known in this country are the ecclesi- 

 astical terriers mode under the provisions of the 87th canon. They 

 consist of a detail of the temporal possessions of the church in the 

 parish. They ought to be signed by the parson, and ore sometimes 

 also signed by the churchwardens and some of the substantial inha- 

 bitants of the parish. Their proper place of custody is the bishop's or 

 archdeacon's registry : a copy also is frequently placed in the parish 

 chest. If a terrier is proved to bo produced from the proper custody, 

 and therefore may bo presumed to be genuine, it is in all instances 

 evidence as against the parson. And in those instances where it has 

 been signed by churchwardens elected by the parish or by the inha- 

 bitants, it is also evidence as against the inhabitants generally 

 against those occupying lauds other than the lands occupied liy the 

 inhabitants who signed it The questions in respect of whieli ,-i terrier 

 is generally employed as evidence are those relating to the glebe, 

 tithes, a modus, &c. 



TEKSTEARIN or TRISTEARIN. [STEARIC ACID.] 



TKKUNCIUS. [As.] 



TESSELATED PAVEMENTS. [Tats ; PAVEMENTS.] 



'IT. SM-'.l: A. I -1.1,. 11 rill r - .|'l:ile T. -.'I lit .hi I/ .ml .lie.', \vilie|| .,, 



used by the ancients for various purposes, and accordingly it consisted 

 of different materials, a* marble, precious stones, ivory, gloss, wood, or 

 mother-of-pearl. Such small tesseno of different colours were used to 

 form the mosaic floors, or pavements in houses [MOSAICS], which were 

 hence called tesselota pavimenta. (Sueton., ' Crcsar,' 46.) The same 

 kinds of cubes, usually made of ivory, bone, or hard wood, and marked 

 on all their six sides, were used by the ancients as dice in games of 

 hazard, just as in our time*. In the earlier times three dice were used 

 in a game, but afterward* only two. 



The word tessera was also employed to signify any token which was 



