How to call RichTextBox from another class?

Question

Visual Basic

Hello everyone,
I have a procedure that needs to add data to a RichTextBox.

Public Sub insertLogHistory(messageStr As String)
     Me.LogHistory.Text = Me.LogHistory.Text + vbCrLf + Date.Now + " - " + messageStr
End Sub

Calling a procedure from another class

Dim FormClass As New Form1()
Public Function HelloWorld() As Boolean
     FormClass.insertLogHistory("Hello world")
End Function

When the procedure is called, no data is added. Any idea why?