_Newmarket, April 13th._--Monday passed off with surprising quiet, and it was considered a most satisfactory demonstration on the part of the Government, and the peaceable and loyal part of the community. Enormous preparations were made, and a host of military, police, and special constables were ready if wanted; every gentleman in London was sworn, and during a great part of the day, while the police were reposing, they did duty. The Chartist movement was contemptible; but everybody rejoices that the defensive demonstration was made, for it has given a great and memorable lesson which will not be thrown away, either on the disaffected and mischievous, or the loyal and peaceful; and it will produce a vast effect in all foreign countries, and show how solid is the foundation on which we are resting. We have displayed a great resolution and a great strength, and given unmistakable proofs, that if sedition and rebellion hold up their heads in this country, they will be instantly met with the most vigorous resistance, and be put down by the band of authority, and by the zealous co-operation of all classes of the people. The whole of the Chartist movement was to the last degree contemptible from first to last. The delegates who met on the eve of the day were full of valour amounting to desperation; they indignantly rejected the intimation of the Government that their procession would not be allowed; swore they would have it at all hazard, and die, if necessary, in asserting their rights. One man said he loved his life, his wife, his children, but would sacrifice all rather than give way.