 Now, we come to the humidity. So, let us recall that the gross lift can be expressed in terms of humidity as PS minus the relative humidity of the wet into E which takes care of the humidity into K into V by TA. Now, the weight of the balloon air will also have one component in the so the pressure will be first added by the super pressure and from that you will subtract the contribution because of the relative humidity. But the balloon air occupies only 1 minus i into V. So, therefore you put 1 minus i into V here. So, if you take the difference of the gross lift after and before that is LG 2 minus LG 1, you get the expression as shown. In this expression, you can see that the PS terms can actually cancel out. So, what will be remaining is just 1 minus RDWV into E1 minus E2. Remember, it is not E2 minus E1 because the minus sign is taken care by changing. The ambient temperature remains the same. We assume that there is no change in any other parameter and volume also remains the same externally. So, the change in the balloon air also will be correspondingly obtained as 1 minus RDWV even minus E2 into 1 minus i KV by TA plus TH. So, therefore the net lift change will be the difference between the gross lift change and the weight of the balloon air and suppose we neglect superheat just to make an expression simpler. If you do not, then you will have a much bigger expression because then you cannot do anything common. But if superheat is neglected, then TA can be taken common and you will get it as E1 minus E2. So if you look at this expression, what we see is that the effect of humidity change E1 to E2 is going to create a change in the net lift. Now, let us see the variation. So, this graph shows the reduction in net static lift for various values of relative humidity versus the ambient air temperature. So, we notice for example that if the ambient air temperature is 35 degrees, then this line is the one which is followed for reduction of the net static lift. So, as the ambient air temperature increases, if you go along the x axis, you will find that the reduction in the net static lift is also increasing. But the lines are different for different values of relative humidity. More effect is felt when you have hot conditions, that means at high temperatures. You can notice that the reduction in the net lift is more when the temperatures are high. If you have only from 0 to 5 degrees, there is hardly any change.