     if active {
       callback("\(NSDate())")
       let dispatchTime = dispatch_time(DISPATCH_TIME_NOW, Int64(Double(NSEC_PER_SEC) * 1))
-      dispatch_after(dispatchTime, isoloationQueue) {
+      dispatch_after(dispatchTime, isolationQueue) {
         self.makeRequest()
       }
     }

  func start() {
    print("Start polling")
    active = true
    dispatch_async(isoloationQueue) {
      self.makeRequest()
    }
  }

class Pollster {
  let callback: (String) -> ()
  private var active: Bool = false
  private let isolationQueue = dispatch_queue_create("com.raywenderlich.pollster.isolation", DISPATCH_QUEUE_SERIAL)
  
  init(callback: (String) -> ()) {
    self.callback = callback
