404 



N E W ENGLAND FARMER 



JVXE 39. I83C. 



CHEMISTRY FOR FARMERS. 



FP.EE CALORIC BECOMF.S LATENT. LAWS OF LA- 

 TENT CALORIC EXPEHIMENTS ILLOSTP.ATING 



THESE LAWS. 



We Stilted in our lust miiiil)er, tliat if a piece of 

 iniii were put into the fire anil lieated, the ca'oric, 

 wlicn it was taken out vvoultl escape in all direc- 

 tion, until the iron had been cooleil down to the 

 temperature of the air which surround it. 



This caloric which thus passed off we called 

 Free Caloric But is not all caloric free ; or is 

 there some that is held imprisoned and cannot es- 

 cape ? Let us experiment upon the suliject. Take 

 two kettles, put five pounds of water into one, and 

 five pounds of ice into the other, and put them 

 both on the same fire, and let them both have the 

 same chance to become heated. Let them hang 

 a certain lime say a quarter of an hour. All this 

 time heat or caloric is going into each kettle 

 equally. At the end of the time, if you examine 

 them by i)uttiiig your hand into each, you vvi 



water. The same thing takes place when a li- 

 quid changes from its liquid state to a solid. This 

 will aiipear evident on a moments reflection — for 

 how could water becoine ice it it did not part w th 

 its heat ? If it did not part with this, it would 

 never freeze. 



If you have an instrument called a Thermome- 

 ter, vou can very easily ascertain how much ca- 

 loric is absorbed or rendered latent by a portion 

 of ice, while it is changing from a solid to a liquid 

 state. If you have a pound of water, wanned or 

 heated, we will say to 172 degrees, and we put in- 

 to it a pound of ice, which is always 32 degrees ; 

 we shall find, when the ice is melted, that the ca- 

 loric has not been equally divided between them, 

 which would make the mean or average heat 102 

 degrees — but that it would be still 32 degrees. 

 If then we substract 32 from 172 we shall find 

 how much heat has been rendered latent, which 

 is 140 degrees. 



There are very many interesting experiments 



find that the five pounds of water have become | which illustrate the laws or principles of latent 



heat, and many of the operations of nature are ex- 

 p'aiued on the princi])lcs which regulate this kind 

 of caloric. 



The very common experiment of making free- 

 zing mixtures, depends upon the substances absorb- 

 ing caloric and rendering it latent. In order to 

 absorb it, it must be obtained from some source, 

 and if that source in contact with the mixture be 

 a liquid, it will be robbed or deprived of its calor- 

 ic by the mixtures, and thus be frozen. For in- 

 stance, if you should mix some common salt and 

 snow together, an intense cold will be | rod need 

 — that is to say, the mixture will take away the 

 heat from the bodies which it touches and render 

 them cold. If you should make the mixture in a 

 bowl and settle a dipper of water into it, the water 

 would be frozen very soon. 



The reason of it is — the salt and snow have a 

 very strong attraction for each other. While 

 combining together, the snow or both, nmst be- 

 come liquid, and to become liquid they must have 

 some heat or caloric to do it. — Tl ey therefore 

 absorb the caloric from the water in the dipj.er 

 and as soon as its caloric is gone, the water free- 

 zes. 



The little instrument called a fire gun or fire 

 pump works on the princ iple, that bodies idiang- 

 ing from a liquid and reriform state to a solid one, 

 or fro;n a thin state to a dense solid, give out ca- 

 loric. This puinj) you ])robably know is nothing 

 more than a strong tube of lead or brass or iron, 

 with a strong bottom. You may make it as you 

 would a small lead cannon, only have it solid and 

 no hole about it, but the bore itself. It should be 

 even and smooth Then fit a plunger or piston, 

 having a piece of leather at the end so that it shall 

 go down air tig-ht. Then fit a piece of pimk or a 

 piece of cotton cloth that has lieen soUked in suit 

 petre water and then thoroughly dried, upon the 

 piston, and ) lunge it down quickly. On pulling it 

 out it will be on fire. ^I'he reason of it is this — 

 when you jjlunge the piston down you press the 

 air into a very small space ; you render it almost 

 so id. As it becomes more pressed and solid, it 

 ^ives ouiits kitent heat which is enough ic set the 

 tinder on fire. 



Another very simple experiment will illustrate 

 this princi|)le. It has been founil that when oil 

 of vitriol and water are put together they iiniteand 

 when they unite it is found that they have con- 

 tracted and do not fiU so much space as they 



po 



hot — and the five pounds of ice have but barely 

 melted and feel as cold as when it was put in. 

 What has be^-ome of the caloric which has been 

 pouring into , it from the fire and yet cannot be 

 perceived while that which has passed into the 

 other kettle is felt in the increased heat of the wa- 

 ter .' It has become swallowed lip or hidden in 

 the ice, — causing it to change from a solid to a li- 

 quid state, but remaining latent in the ice or fluid 

 into which the ice is changed. It cannot there- 

 fore be called Free Caloric, and it has received the 

 name of Latent Caloric, 



Again, after the ice is melted let us continue 

 the heat, the water begins to grow warm — it in- 

 creases in heat till it boils — the moment it boils, 

 we see the water changed from a liquid state. It 

 becomes a vapor and rises up into the air. The 

 water has arrived to a certain degree of heat, you 

 may pour the heat in all day after this and it will 

 not grow any hotter. What becomes of the ca- 

 loric or heat which passes in? Why does it not 

 make the water hotter and hotter. Uecause, after 

 tlie water begins to boil, a certain portion of the 

 caloric is swallowed np in the steam and becoiTies 

 Latent as it did before. I'ut a cover upo^i your 

 kettle- anil confine the steam .Tod you may then in- 

 crease the heat to a great degree, even sufiicieut to 

 melt lead. 



Here then wo have learned that when a solid 

 substance becomes changed to a liquid state, it 

 must swallow up or absorb a portion of caloric and 

 render it Latent; and further, that when a liquid 

 cliai ges from a liquid to a vapor or aeriform 

 state, it must absorb more caloric and render it 

 also Latent. Well, suppose we change the pro- 

 cess ? If a liquid must swallow up and render 

 latent a large quantity of caloric when clianging to 

 a vapor, if you again change it from a vapor to a 

 liquid will it give up the caloric and roiider it 

 iree ? It certainly will, for if the absorbijig the 

 caloric was the cause of its becoming vapor, it 

 certainly cannot be reduced to a liquid again, un- 

 less it parts with h^ Latent caloric, and if it parts 

 with this, it immediately becomes liberated or 

 free, and is perceptible to the senses. This is 

 done when a large quantity of water is heated by 

 passing steam into it. A large vat of water at a 

 rlistance from a steamer or boiler may be heated 

 by suflering a tube to c-arry steam into it. The 

 steam becomes condensed in the water and there- 

 by gives up its latent caloric which heals the 



would if separate. By contracting they must of 

 course, become more solid, and to become more 

 solid, they must givj out heat whioh was before 

 latent — accordingly the mixture gives out heat 

 enough to make a small quantity of water boil. 



Another very common incident illustrates this 

 law. You have seen lime slacked with water. A 

 great heat is produced, and even something which 

 looks like smoke. From whence comes the heat.' 

 It must come from the water — even the cold wa- 

 ter which you put on, and which you may drink 

 without danger, and yet by mingling it with lime, 

 suflieieiit heat is given out to set buildings and 

 ships on fire. The reason is that the lime and the 

 water have a strong affinity or attraction for each 

 other. They combine, the water becomes solid, 

 but in becoming solid must give out its latent ca- 

 loric. Every pound of water giving out 140 de- 

 grees. It would require but a few pounds to af- 

 ford heat enough to set dry wood on fire. Tlie 

 smoke is little particles of lime carried up by the 

 steam. 



'i'hus we see that there ia another and n very 

 important modification of caloric besides Free Ca- 

 loric, and also that bodies changing from a solid 

 to a liquid state, absorb and render caloric Latent ; 

 and that reversing the jirocess, passing from a li- 

 quid to a solid state they give it out and render it 

 free. 



Other modifications will be given in our next 

 number. — Maine Par. 



RAISING OP CHICKEXS. 



Sue. — I he subject upon which 1 am about to 

 write, may excite a smile upon the faces of some, 

 but if I succeed in rendering even a small service 

 to any, the object will be accomplished. He 

 thinks he may throw out a few hints that may be 

 useful in increasing the number and quality of an 

 animal that is so universally made to conduce to 

 the luxury of the table, and the proper sustenance 

 of the human system. 



In the first place, then, 1 would advise those in- 

 terested to procure for themselves a good breed of 

 fowls. The pair I sent you last fall, I consider 

 nearer to perfection, in all respects, than those of 

 any other breed. I call them the Ostrich breed, 

 from their strong resemblance when about half 

 grown to that famous bird. They are large — 

 their habits are veiy domestic — they hy well — 

 set well — hatch well — and nurse well — and 

 their flesh is very delicious. Have a well shel- 

 tered place for them to roost in, with a sufiicient 

 number of places for them to lay their eggs. Let 

 your box be about a toot wide, and about 15 inch- 

 es high — with (lartitions about ten inches apart. 

 I he box to be enclosed o :i evei-y side, with the ex- 

 ception of about six inches of the front, and that 

 the upper part — place the box enough against the 

 .wall to prevent the depredations of children, &c. 

 I he hen is fond of a small aperture to creep into 

 tor the purpose of laying. At the proper setting 

 season remove your eggs carefully every night in- 

 to a safe place, to prevent their freezing or getting 

 much chilled, which will prevent their hatching. 

 No "nest egg" is necessary upon this plan. 'I he 

 nest egg, in my opinion, seldom produces a chick- 

 en, ear.y in the spring because of its generally 

 having been chilled. 



While the laying business is very brisk, (irepare 

 as many setting boxes as yini may think fit. Let 

 them be about eighteen inches square, enclosed 

 on every side, witli a loose cover for the top, not 



