The Keynesians, have offered a demand area explanation from the business cycle. According to them, the fluctuations in output and employment near your vicinity are caused by variances in aggregate demand. The ups and downs in aggregate demand are caused by modifications in our volume of investment. The volume of investment is usually directly associated with the little efficiency of capital. The investment improves in response to raised marginal performance of capital and decreases with all the fall in the money expectations of the entrepreneurs. The Keynesians further put forward the theory of multiplier which shows how the enhance or decline in investment triggers multiplied changes in income and employment and thus heightens a boom or deepens a depression. The Keynesians failed as they did not explain the cyclical characteristics of the pros and cons in business circuit. J. R. Hicks and Professor Samuelson put forward a fresh theory of business circuit named because Multiplier and Accelerator Theory of business cycle. 

Multiplier and Accelerator Theory
According to J. R. Hicks and Samuelson, the multiplier exclusively cannot describe the cyclical nature with the business cycle. It is the conversation between the multiplier and accelerator that talks about the breakthrough of different phases of organization cycle. The multiplier tells us that a change in the level of autonomous investment creates a relatively higher change in the amount of national profits. The gas theory declares that the current investment spending depends positively on the expected future growth of real GROSS DOMESTIC PRODUCT. When real GDP development is anticipated to be substantial, firms assume that all their investment in plants and equipment will probably be profitable. They will, therefore , enhance their total expenditure spending. 

The concept of ignition is certainly not rival for the concept of multiplier. They are parallel concepts. The multiplier shows the effect of changes in autonomous investment to changes in income' and employment. The...