The sparrows also joined the morning. They sat in thousands around her dead body. They did not chirrup. Nor did they touch the crumbs of bread thrown to them by the narrator's mother. They flew away quietly when the dead body was carried off for cremation.

Let us consider the two systems A and B and both the systems are isolated by adiabatic wall. That means neither energy nor matter can enter or leave either system. In this case both the systems cannot communicate through this wall since it is an adiabatic wall.
Now we replace the adiabatic wall with diathermic wall, which permits the flow of energy in the form of heat and finally it will reach thermal equilibrium.

Now instead of two systems, consider three systems A, B and C. The systems A and B are separated by an adiabatic wall, while each is in contact with a third system C, through a conducting wall.

The states of the systems which is characterized by certain macroscopic variables, will change until both A and B come into thermal equilibrium with C.

After this stage the adiabatic wall between the systems A and B is replaced by a conducting wall and the system C is insulated from A and B by an adiabatic wall.

Observation: We found that the states of A and B remains as in the previous case. That means both the systems are in thermal equilibrium with each other.

Observation Leads to Defining Law: "If two systems are at the same time in thermal equilibrium with a third system, they are in thermal equilibrium with each other. If A and C are in thermal equilibrium with B, then A is in thermal equilibrium with B". This statement is called as Zeroth Law.

Practically this means that all three are at the same temperature, and it forms the basis for comparison of temperatures.

The Zeroth law is more fundamental than first and second law even though actually it was stated much later than both the First and Second Laws of thermodynamics. It is so named because it logically precedes the First and Second Laws of Thermodynamics.

<font face="Verdana"><font style="text-shadow: rgba(255, 255, 255, 0.3) 0px 1px 1px; user-select: initial !important; line-height: 1.5em; -webkit-font-smoothing: antialiased; font-family: roboto, sans-serif; color: rgb(51, 51, 51); font-size: 18px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial;">The Zeroth Law clearly suggests that when two systems A and B, are in thermal equilibrium then there must be a physical quantity that has the same value for both the systems.</font></font>

<font face="Verdana"><font style="text-shadow: rgba(255, 255, 255, 0.3) 0px 1px 1px; user-select: initial !important; line-height: 1.5em; -webkit-font-smoothing: antialiased; font-family: roboto, sans-serif; color: rgb(51, 51, 51); font-size: 18px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial;">This physical quantity is a new thermodynamic parameter whose value is equal for two systems in thermal equilibrium and is called as temperature (T). This is the only property which allows us to think of the possible make and use of thermometer.</font></font>

<font face="Verdana"><font style="text-shadow: rgba(255, 255, 255, 0.3) 0px 1px 1px; user-select: initial !important; line-height: 1.5em; -webkit-font-smoothing: antialiased; font-family: roboto, sans-serif; color: rgb(51, 51, 51); font-size: 18px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial;">If A and B are separately in equilibrium with C, then</font></font>
<font face="Verdana"><font style="text-shadow: rgba(255, 255, 255, 0.3) 0px 1px 1px; user-select: initial !important; line-height: 1.5em; -webkit-font-smoothing: antialiased; font-family: roboto, sans-serif; color: rgb(51, 51, 51); font-size: 18px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial;">T_A = T_C</font></font><font color="#ff0000"><font face="Verdana"><font style="text-shadow: rgba(255, 255, 255, 0.3) 0px 1px 1px; user-select: initial !important; line-height: 1.5em; -webkit-font-smoothing: antialiased; font-family: roboto, sans-serif; font-size: 18px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial;"> </font></font></font><font face="Verdana"><font style="text-shadow: rgba(255, 255, 255, 0.3) 0px 1px 1px; user-select: initial !important; line-height: 1.5em; -webkit-font-smoothing: antialiased; font-family: roboto, sans-serif; color: rgb(51, 51, 51); font-size: 18px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial;">and T_B = T_C</font></font>
This leads to T_A = T_B

<font face="Verdana"><font style="text-shadow: rgba(255, 255, 255, 0.3) 0px 1px 1px; user-select: initial !important; line-height: 1.5em; -webkit-font-smoothing: antialiased; font-family: roboto, sans-serif; color: rgb(51, 51, 51); font-size: 18px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-style: initial; text-decoration-color: initial;">i.e. the systems A and B are also in thermal equilibrium.</font></font>

1. Rate of dividend payable on preference shares is higher than the rate of interest on debenture
2. The claim of equity shareholders over assets of the company is affected by the issue of preference share capital.
3. Investors willing to take risk and earn higher returns do not prefer preference shares.
4. Since dividend paid is not deductible from profits as expense, there is no tax saving as in case of interest on debentures or loans.
5. There is no consistent return for the investors because the dividend is payable to the preference shareholders only when the company earns profit.