 When we parted we had just mentioned the word products from the candle for when the candle burns We found we were able to get various products from it There was one substance which was not obtained when the candle was burning properly Which was charcoal or smoke and there was some other substance that went upwards from the flame Which did not appear as smoke but took some other form and made part of that general current Which ascending from the candle upwards becomes invisible and escapes there were also other products to mention you remember that in that Rising current having its origin at the candle. We found that one part was condensable against a cold spoon and another part was Incondensable we will first take the condensable part and examine it and strange to say we find that that part of the product is just water Nothing but water on the last occasion I spoke of it incidentally merely saying that water was produced among the condensable products of the candle But today I wish to draw your attention to water that we may examine it carefully Especially in relation to the subject and also with respect to its general existence on the surface of the globe Now having previously arranged an experiment for the purpose of condensing water from the products of the candle My next point will be to show you that this water and perhaps one of the best means that I can adopt for showing its Presence is to exhibit a very visible action of water And then to apply that test to what is collected as a drop at the bottom of the vessel a Small piece of potassium shows the presence of water by lighting up and floating about burning with a violent flame You see a drop of water a condensed product of the candle hanging from under the surface of the dish I will show you the potassium has the same action upon it as upon the water in the dish in the experiment We have just tried I will take a drop upon a glass slide and when I put the potassium to it You'll see it once from it taking fire that there is water present Now that water was produced by the candle water is one individual thing it never changes We can add to it by careful adjustment for a little while or we can take it apart and get other things from it But water as water remains always the same either in a solid liquid or fluid state And now to go into the history of this wonderful production of water from combustibles and by combustion I must first of all tell you that this water may exist in different conditions And although you may now be acquainted with all its forms They still requires to give a little attention to them for the present so that we may perceive how the water when it goes through its Protein changes is entirely and absolutely the same thing whether it's produced from a candle by Combustion or from the rivers or ocean first of all water when at the coldest is ice now We scientists speak of water as water whether it be in its liquid or solid or gaseous state We speak of it chemically as water water is a thing compounded of two substances One of which we have derived from the candle and the other which we shall find elsewhere Water may occur as ice ice changes back into water when the temperature is raised Water also changes into steam when it's warmed enough the water Which I have before me is in its densest state and although it changes in condition and form and in many other Qualities it still is water and whether we change it into steam by heat or whether we alter it into ice by cooling It increases in volume in the first case very largely and wonderfully and in the second very strangely and powerfully For instance, I have this metal bottle into which I poured a little water into it I'm converting the water into steam for the purpose of showing you the different volumes Which water occupies in its different states of liquid water and water vapor or steam See what a stream of vapor is issuing from this bottle You observe that we must have made it quite full of steam to have it sent out in that great quantity And now as we can convert the water into steam by heat We convert it back into liquid water by the application of cold and if we take a watch glass and Hold it over the steam see how soon it gets damp with water It will condense until the glass is warm it condenses the water which is now running down the sides of it I have here another experiment to show the condensation of water from a vapor state back into a liquid state in the same way as The vapor one of the products of the candle was condensed against the bottom of the dish and obtained in the form of water And to show you how truly and thoroughly these changes take place I will take these bottle which is now full of steam and close the top Which will see what takes place when we cause this water or steam to return back to the fluid state by cooling it in water You see what has happened if I had closed the lid and still kept the heat applied to it It would have burst the vessel yet when the steam returns to the state of liquid water the bottle collapses There being a vacuum produced inside the condensation of the steam I show you these experiments for the purpose of pointing out that in all these occurrences There is nothing that changes the water into any other thing it still remains water And so the vessel is obliged to give way and has crushed inwards as in the other case by the further application of heat it would have been blowing outwards and What do you think the bulk of that water is when it assumes the vaporous condition a cubic inch of water will expand to a Cubic foot of steam and on the contrary the application of cold will contract that large amount of steam into this small quantity of water Let us now take the case of water changing into ice We can affect that by cooling the water in a dry ice Acetone bath and I should do so to show you that when water becomes ice it changes in volume in an extraordinary way These bottles are made of cast iron. They're very strong and very thick I suppose they are each a third of an inch in thickness I filled this one with water to exclude all air and I'll screw the plug in tightly We shall see that when we freeze the water in the vessel It will not be able to hold the ice and the expansion within will break it into pieces No communication will take place you observe between the water in the bottle and the ice in the outer bowl But there will be a conveyance of heat from one to the other The cold has taken possession of the bottle in its contents all the iron was thick the ice had burst to the sunder You see some ice partly enclosed by the covering of iron Which is too small for them because the ice is larger in bulk than the water You know very well that ice floats on water Why because the ice is larger than the quantity of water which can produce it and therefore the ice weighs the lighter And the water is the heavier To return to our quiet philosophy We shall not in future be deceived therefore by any changes that are produced in water Water is the same everywhere whether produced from the ocean or from the flame of the candle Where then is the water which we get from a candle? I must anticipate a little and tell you it evidently comes as to part of it from the candle But is it within the candle beforehand? No, it is not in the candle and it is not in the air round about the candle which is necessary for its combustion It is neither in one nor the other But it comes from their combined action apart from the candle apart from the air and this we have now to trace So that we may understand thoroughly what is the chemical history of a candle when we have it burning on our table How shall we get at this? I myself know plenty of ways But I want you to get at it from the association in your minds of what I've already told you I think you can see a little in this way. I'll use electricity to pull water to pieces This power supply makes it as though I were applying heat to cause the water to appear to boil When we separate or electrolyze water into its parts we get two volumes of one gas and one of another The gases produced are not steam steam is condensable into water And when you lower the temperature of steam you convert it back into fluid water As you know water is liquid at room temperature notice that this gas which I've collected it does not become a liquid I will take another test and apply it to this gas If I now apply a light to the mouth of the test tube it ignites with a slight noise That tells you that it is not steam steam puts out a fire It does not burn, but you saw that when I had in this test tube Burt We may obtain this substance equally from water produced from the candle flame as from any other source Here is a vial full of the same gas. I will show you something most interesting It is a combustible gas, but it is also less dense than air Steam will condense this body will rise in the air and not condense Suppose I take another vial empty of all but air if I examine with a flame I shall find that it contains nothing but air I will now take this vial full of the gas that I'm speaking of and deal with it as though It were a light body. I will hold both upside down and turn the one up under the other And now what does the vial contain that had the gas procured from the steam you will find it only contains air But look Here is the combustible substance which I have poured out of the one vial into the other It still preserves its quality and condition and independence and therefore is the more worthy of our consideration as belonging to the products of candle This is what we get from water the same substance which are contained in the candle Let us now trace distinctly the connection between these two points This is hydrogen a body classed among those things which in chemistry we call elements because we can get nothing else out of them A candle is not an elementary body because we can get carbon out of it We can get this hydrogen out of it or at least out of the water which it supplies And this gas has been so named hydrogen because it is that element which in association with another element generates water This hydrogen is a very beautiful substance. It is so light that it carries things up It is far lighter than the atmosphere and I dare say I can show you this by an experiment Here is our tank of hydrogen and here are some soap suds I have a rubber tube connected with the hydrogen tank and at the end of it a plastic pipe now I could blow bubbles with my breath or Blow bubbles by means of the hydrogen you observe how the bubbles fell downwards when I blew them with my warm breath But notice the difference when I blow them with hydrogen It shows you how light this gas must be in order to carry with it Not merely the ordinary soap bubble, but the larger portion of a drop hanging to the bottom of it I can show its lightness in a better way than this larger bubbles than these may be so lifted up Indeed in former times balloons used to be filled with this gas Water also contains oxygen oxygen as you will immediately imagine exists in the atmosphere For how should the candle burn to produce water without it such a thing would be absolutely impossible and chemically impossible without oxygen Now as regards this very property of oxygen supporting combustion which we may compare to air I'll take a piece of candle to show it to you in a rough way and the result will be rough You see the combustion in air. How will it burn in oxygen? I have here a jar of oxygen for you to compare the action of this gas with that of air See how brightly and how beautifully it burns. Is it wonderful how great the supporting powers of oxygen are as regards combustion But it does not affect merely the combustion of hydrogen or carbon or the candle But it exalts all combustions of the common kind. We must now for a little while longer look at it with respect to hydrogen I'm now about to set fire to oxygen a hydrogen mixed in the proportion in which they occur in water Here is a vessel of soap bubbles made with one volume of oxygen and two volumes of hydrogen Exactly the same nature as the gas we obtain from electrolysis I will take a bubble in my hand and you will perhaps think I'm acting oddly in this experiment But it is to show you that we must not always trust to noise and sound but rather to real facts This oxygen united with the hydrogen as you saw by the phenomenon and heard by the sound with the utmost readiness of action And all its powers were taking up in its neutralization of the qualities of the hydrogen So now I think you will perceive the whole history of water with reference to oxygen in the air from what we have said before Why does a piece of potassium decompose water because it finds oxygen in the water? What is set free when I put it in the water? It sets free hydrogen and the hydrogen burns but the potassium itself combines with oxygen and this piece of potassium And taking the water apart the water You may say derived from the combustion of the candle takes away the oxygen which the candle took from the air And so sets the hydrogen free and even if I take a piece of ice and put a piece of potassium upon it The beautiful affinities by which the oxygen and the hydrogen are related are such that the ice will absolutely set fire to the Potassium it produces a sort of volcanic action It will be my place when next we meet having pointed out these anomalous actions to show you that none of these Extra and strange effects are met with by us that none of these strange and injurious actions take place when we are burning Not merely a candle but gas in our homes or fuel in our fireplaces So long as we confine ourselves within the laws that nature has made for our guidance